We describe a 6-min HPLC method to measure the total concentrations of the most important thiols in plasma and urine–cysteine, homocysteine, cysteinylglycine, and glutathione–as well as the concentrations in plasma and urine, respectively, of cysteamine and 2-mercaptopropionylglycine, two compounds used to treat disorders of cysteine metabolism. Precolumn derivatization with bromobimane and reversed-phase HPLC were performed automatically by a sample processor. Throughput was up to 100 samples in 24 h. The within-run CV ranged from 0.9% to 3.4% and the between-run CV ranged from 1.5% to 6.1%. Analytical recovery was 97–107%, with little difference between plasma and urine samples. The detection limit was ∼50 nmol/L for all the analytes studied. Thiol concentrations were determined in the plasma of 206 healthy donors and in the urine of 318 healthy donors distributed for age and sex. Mean values of plasma cysteine and homocysteine were significantly lower in infants (ages, <1 y) compared with other age groups (P <0.005). In adults, mean plasma homocysteine values were higher in males than in females (9.2 vs 6.7 μmol/L, P <0.0001) and in the 6- to 10-year-old group (P <0.05). Mean values for glutathione and cysteinylglycine were not sex- and age-dependent. In urine, both cysteine and homocysteine showed a wide range of variation.

The erythrocyte glutathione S-transferase (e-GST) is a member of a superfamily of inducible enzymes involved in cell detoxification that shows an increased expression in chronic kidney disease (CKD) patients. We propose a new automated analysis procedure for e-GST activity that has been validated in 72 CKD patients and 62 maintenance hemodialysis patients (MHD). Regression analysis was carried out to assess association between e-GST activity data, main clinical variables, and plasma homocysteine (Hcy), a modified sulfur amino acid known as potential risk factor for cardiovascular disease that is increased above normal levels in more than 90% of the uremic patients. An increased e-GST activity was confirmed in MHD patients (N=62; 10.2±0.4 U/gHb) compared with healthy subjects (N=80; 5.8±0.4 U/gHb), and as an original finding, a significant increase of e-GST activity was observed in pre-dialysis CKD patients with a positive correlation with disease severity weighted according to the four stages of "Kidney Disease Outcomes Quality Initiative" classification (7.4±0.5, 8±1, 9.5±0.6, 12±1 U/gHb, respectively). No correlation was found between e-GST activity and hemoglobin, transferrin, blood iron and the markers of systemic inflammation and renal function such as alpha-1 acid glycoprotein and high-sensitive C-Reactive Protein, beta-2 microglobulin and the index of malnutrition-inflammation PINI, while a significant correlation was observed for the first time between plasma Hcy and e-GST activity (r2=0.64, P<0.0001) in MHD patients. Hcy, however, was not identified as an inhibitor of e-GST enzyme. The results in this study suggest the potential for automated e-GST analysis as a valuable tool to further explore phase II-related uremic toxicity in CKD and MHD patients.

The exposure of blood to an artificial surface such as the haemodialysis membrane results in the nearly instantaneous deposition of a layer of plasma proteins. The composition of the protein layer profoundly influences all subsequent events, and to a large extent determines the biocompatibility of the biomaterial. In the present study, we examine the protein adsorption capacity and coagulation profiles of the polysulfone-based helixone material in comparison to cellulose triacetate. A differential profiling investigation using shotgun proteomics data-independent analysis was applied to eluates obtained with each membrane after a dialysis session, in order to assess the function of desorbed proteins. Functional classification and network analysis performed using bioinformatics tools shed light on the involvement of adsorbed proteins into important molecular processes, such as lipid transport and metabolism, cell growth differentiation and communication, and the coagulation cascade. The collected evidence was further validated by targeted mass spectrometry using selected reaction monitoring on proteotypic transitions of key protein effectors, confirming the different panels of adsorbed protein on each membrane. The coagulation profile during haemodialysis of patients under polysulfone-based helixone filter cartridges was also assessed showing a slightly higher platelet activation profile after the dialysis session. The overall collected evidence highlights a modulation of the coagulation biological pathway during haemodialysis, which is largely influenced by the biomaterial used.

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Vitamin C has been shown to play a significant role in suppressing progression of leukemia through epigenetic mechanisms. We aimed to study the role of vitamin C in acute myeloid leukemia (AML) biology and clinical course. To this purpose, the plasma levels of vitamin C at diagnosis in 62 patients with AML (including 5 cases with acute promyelocytic leukemia, APL),7 with myelodysplastic syndrome (MDS), and in 15 healthy donors (HDs) were studied. As controls, vitamins A and E levels were analysed. Expression of the main vitamin C transporters and of the TET2 enzyme were investigated by a specific RQ-PCR while cytoplasmic vitamin C concentration and its uptake were studied in mononuclear cells (MNCs), lymphocytes and blast cells purified from AML samples, and MNCs isolated from HDs. There were no significant differences in vitamin A and E serum levels between patients and HDs. Conversely, vitamin C concentration was significantly lower in AML as compared to HDs (p&lt;0.0001), inversely correlated with peripheral blast‐counts (p=0.029), significantly increased at the time of complete remission (CR) (p=0.04) and further decreased in resistant disease (p=0.002). Expression of the main vitamin C transporters SLC23A2, SLC2A1 and SLC2A3 was also significantly reduced in AML compared to HDs. In this line, cytoplasmic vitamin C levels were also significantly lower in AML-MNCs versus HDs, and in sorted blasts compared to normal lymphocytes in individual patients. No association was found between vitamin C plasma levels and the mutation profile of AML patients, as well as when considering cytogenetics or 2017 ELN risk stratification groups. Finally, vitamin C levels did not play a predictive role for overall or relapse-free survival. In conclusion, our study shows that vitamin C levels are significantly decreased in patients with AML at the time of initial diagnosis, further decrease during disease progression and return to normal upon achievement of CR. Correspondingly, low intracellular levels may mirror increased vitamin C metabolic consumption in proliferating AML cells.

Academic centers utilize sequential clinical and neuroimaging assessments, including morphometric ratios, to obtain an unequivocal diagnosis of the non-synucleinopathic forms of Parkinsonism, such as progressive supranuclear palsy (PSP), however, a 1-2 year follow-up is required. The on-going long-lasting trials using anti-tau antibodies for PSP patients might therefore be biased by the incorrect enrollment of Parkinson's disease (PD) patients manifesting early axial signs. This perspective study aimed at achieving two major goals: first, to summarize the established biomarker candidates found in cerebrospinal fluid (CSF) in probable PSP patients, including low p-tau and altered neurofilaments. Second, we share our recent data, from CSF samples of well-selected PSP subjects, attributable to both main variants (and revisited in light of MDS criteria), who were followed for 1 year before and 2 years after lumbar puncture. We found a significantly high level of noradrenaline (NE) in these patients, similar to controls, when compared to PD patients. In contrast, CSF samples, in PD, showed a significant reduction in CSF NE and its major metabolite, which confirmed that PD is a multi-system disease involving several endogenous pathways. The NE axis impairments were prominent in PSP featuring worse NPI. It might represent a counterpart to the early and peculiar psycho-pathological profiles that are observed in tauopathies. In conclusion, we highlight that CSF biomarkers, which are easy to collect, can provide rapid insights as diagnostic tools. Early alterations in endogenous NE machinery in atypical Parkinsonism may represent a specific risk trait in forms characterized by a worse prognosis.

We report the first data on 25-hydroxyvitamin D plasma levels in natural populations of three species of land iguana endemic to the Galápagos Islands (Conolophus marthae, C. subcristatus, and C. pallidus). The pigment is present throughout the whole body in the skin of C. subcristatus and C. pallidus. On the contrary, pigment is not present in the skin of an extended part of the body in C. marthae. The only existing population of C. marthae is syntopic with a population of C. subcristatus, and the two species are closely related. These circumstances would suggest that, under the assumption that the species show a similar basking behavior and in the absence of compensatory mechanisms, lighter pigmentation should favor higher vitamin D levels. Thus, C. marthae, compared with C. subcristatus in Wolf Volcano, could show higher levels of 25(OH)D plasma levels, or equal, if compensatory mechanisms exist. The three species showed levels in the range of average values for healthy iguanas. However, contrary to the expectation, C. marthae consistently exhibited the lowest 25(OH)D plasma levels. We discuss possible factors affecting vitamin concentration and hypothesize that C. marthae may use the habitat to limit exposure to the high UVB irradiation at Wolf Volcano.