Trimethylamine-N-oxide (TMAO) is a small organic molecule, derived from the intestinal and hepatic metabolism of dietary choline and carnitine. Although the involvement of TMAO in the framework of many chronic diseases has been recently described, no evidence on its putative role in the central nervous system has been provided. The aim of this study was to evaluate whether TMAO is present at detectable levels in human cerebrospinal fluid (CSF). CSF was collected for diagnostic purposes from 58 subjects by lumbar puncture and TMAO was quantified by using liquid chromatography coupled with multiple-reaction monitoring mass spectrometry. The molecule was detected in all samples, at concentrations ranging between 0.11 and 6.43 µmol/L. Further analysis on CSF revealed that a total of 22 subjects were affected by Alzheimer’s disease (AD), 16 were affected by non-AD related dementia, and 20 were affected by other neurological disorders. However, the stratification of TMAO levels according to the neurological diagnoses revealed no differences among the three groups. In conclusion, we provide the first evidence that TMAO can be assessed in human CSF, but the actual impact of this dietary metabolite in the patho-physiolgy of the central nervous system requires further study.

Over the years, the relationship between high-density lipoprotein (HDL) and atherosclerosis, initially highlighted by the Framingham study, has been revealed to be extremely complex, due to the multiple HDL functions involved in atheroprotection. Among them, HDL cholesterol efflux capacity (CEC), the ability of HDL to promote cell cholesterol efflux from cells, has emerged as a better predictor of cardiovascular (CV) risk compared to merely plasma HDL-cholesterol (HDL-C) levels. HDL CEC is impaired in many genetic and pathological conditions associated to high CV risk such as dyslipidemia, chronic kidney disease, diabetes, inflammatory and autoimmune diseases, endocrine disorders, etc. The present review describes the current knowledge on HDL CEC modifications in these conditions, focusing on the most recent human studies and on genetic and pathophysiologic aspects. In addition, the most relevant strategies possibly modulating HDL CEC, including lifestyle modifications, as well as nutraceutical and pharmacological interventions, will be discussed. The objective of this review is to help understanding whether, from the current evidence, HDL CEC may be considered as a valid biomarker of CV risk and a potential pharmacological target for novel therapeutic approaches.

Here, a formulation of silver nanoparticles (AgNPs) and two natural polymers such as alginate (ALG) and nanocrystalline cellulose (CNC) was developed for the 3D printing of scaffolds with large surface area, improved mechanical resistance and sustained capabilities to promote antimicrobial and cytotoxic effects. Mechanical resistance, water content, morphological characterization and silver distribution of the scaffolds were provided. As for applications, a comparable antimicrobial potency against S. aureus and P. aeruginosa was demonstrated by in vitro tests as function of the AgNP concentration in the scaffold (Minimal Inhibitory Concentration value: 10 mg/mL). By reusing the 3D system the antimicrobial efficacy was demonstrated over at least three applications. The cytotoxicity effects caused by administration of AgNPs to hepatocellular carcinoma (HepG2) cell culture through ALG and ALG/CNC scaffold were discussed as a function of time and dose. Finally, the liquid chromatography-mass spectrometry (LC-MS) technique was used for targeted analysis of pro-apoptotic initiation and executioner caspases, anti-apoptotic and proliferative proteins and the hepatocyte growth factor, and provided insights about molecular mechanisms involved in cell death induction.

The Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) involvement in Alzheimer’s disease (AD) is poorly investigated. We evaluated the in vitro PCSK9 modulation of astrocyte cholesterol metabolism and neuronal cholesterol supplying, which is fundamental for neuronal functions. Moreover, we investigated PCSK9 neurotoxic effects. In human astrocytoma cells, PCSK9 reduced cholesterol content (−20%; p < 0.05), with a greater effect in presence of beta amyloid peptide (Aβ) (−37%; p < 0.01). PCSK9 increased cholesterol synthesis and reduced the uptake of apoE-HDL-derived cholesterol (−36%; p < 0.0001), as well as the LDL receptor (LDLR) and the apoE receptor 2 (ApoER2) expression (−66% and −31%, respectively; p < 0.01). PCSK9 did not modulate ABCA1- and ABCG1-cholesterol efflux, ABCA1 levels, or membrane cholesterol. Conversely, ABCA1 expression and activity, as well as membrane cholesterol, were reduced by Aβ (p < 0.05). In human neuronal cells, PCSK9 reduced apoE-HDL-derived cholesterol uptake (−41%; p < 0.001) and LDLR/apoER2 expression (p < 0.05). Reduced cholesterol internalization occurred also in PCSK9-overexpressing neurons exposed to an astrocyte-conditioned medium (−39%; p < 0.001). PCSK9 reduced neuronal cholesterol content overall (−29%; p < 0.05) and increased the Aβ-induced neurotoxicity (p < 0.0001). Our data revealed an interfering effect of PCSK9, in cooperation with Aβ, on brain cholesterol metabolism leading to neuronal cholesterol reduction, a potentially deleterious effect. PCSK9 also exerted a neurotoxic effect, and thus represents a potential pharmacological target in AD.

Lipid metabolism derangement contributes to increased cardiovascular risk in Rheumatoid Arthritis (RA). It is still debated whether and how tocilizumab, an interleukin-6 receptor inhibitor used in active RA, impacts cardiovascular risk. We studied the effect of tocilizumab on the regulation of macrophage cholesterol homeostasis, measuring patient serum ability to respectively load (cholesterol loading capacity, CLC) and discharge (cholesterol efflux capacity, CEC) cells with cholesterol. Patients with RA (n = 8) were studied before and after 4 and 12 weeks of tocilizumab treatment. CLC was measured by a fluorimetric assay of intracellular cholesterol content in human macrophages and CEC was measured for the three main pathways, mediated by the transporters Scavenger Receptor class B-type I (SR-BI), ATP binding cassette-G1 (ABCG1) and -A1 (ABCA1) in specific cell models. After 12 weeks of tocilizumab treatment, serum LDL cholesterol levels were increased, while CLC was reduced. HDL cholesterol levels were unchanged, but CEC was significantly ameliorated for the SR-BI and ABCG1 pathways with respect to baseline. Tocilizumab reduces LDL pro-atherogenic potential despite increasing their serum levels and increases HDL protective activity in RA. The data of our pilot study suggest that tocilizumab regulates lipoprotein function in selected patient populations and lay the groundwork for future larger studies.

Active dressings acting on multiple fronts are requested in the field of care for chronic skin ulcers in order to ameliorate patient compliance and tissue restoration. Currently, three-dimensional polymeric hydrogels are widely investigated; however, no prototypes aiming to control oxidative stress and bacterial proliferation in the wound bed have been developed up until now. The present work describes the formulation of a novel chitosan-based printable material containing α-tocopherol at stable dosages to obtain reproducible 3D scaffolds possessing antioxidant and antimicrobial activity without the use of organic solvents. Stability assays mimicking the manufacturing process and storage conditions reveal no significant drug loss. Chemico-physical characterizations including porosity and behavior after dehydration/hydration demonstrate that the dressings are highly porous, can be dehydrated up to 80%, and can recover more than 90% of water upon 1 h of rehydration. Elasticity determined by stress/strain tests was higher than human skin and was sufficiently resistant for potential clinical manipulation. Footage of fibroblasts in in vitro cultures demonstrated the biocompatibility of the constructs over 28 days. Finally, scaffolds loaded with α-tocopherol showed dose-dependent antioxidant activity (up to 80% in less than 1 h), while antimicrobial action versus multi-drug resistant strains of Pseudomonas aeruginosa and Staphilococcus aureus was assessed by inhibition rings obtained through the Kirby–Bauer technique. The proposed hydrogels can be useful as dressings for the treatment of chronically infected wounds.