Oxidative status in different settings and with different methodological approaches compared by Receiver Operating Characteristic curve analysis

Objectives: To test the performance of different analytical approaches in highlighting the occurrence of deregulated redox status in various physio-pathological situations. Design and methods: 35 light and 61 heavy smokers, 19 chronic renal failure, 59 kidney transplanted patients, and 87 healthy controls were retrospectively considered for the study. Serum oxidative stress and antioxidant status, assessed by spectrophotometric Reactive Oxygen Metabolites (d-ROMs) and Total Antioxidant Capacity (TAC) tests, respectively, were compared with plasma free (F-MDA) and total (T-MDA)malondialdehyde, both quantified by isotope-dilution-gas chromatography\u2013mass spectrometry (ID-GC\u2013MS). Sensitivity, specificity and cut-off points of T-MDA, F-MDA, d-ROMs and TAC were evaluated by both Receiver Operating Characteristic (ROC) analyses and area under the ROC curve (AUC). Results: Only T-MDA assay showed a clear absence of oxidative stress in controls and significant increase in all patients (AUC 1.00, sensitivity and specificity 100%). Accuracy was good for d-ROMs (AUC 0.87, sensitivity 72.8%, specificity 100%) and F-MDA (AUC 0.82, sensitivity 74.7%, specificity 83.9%), but not high enough for TAC to show in patients impaired antioxidant defense (AUC 0.66, sensitivity 52.0%, specificity 92.9%). Conclusions: This study reveals T-MDA as the best marker to detect oxidative stress, shows the ability of d-ROMs to identify modified oxidative status particularly in the presence of high damages, and evidences the poor TAC performance. d-ROMs and TAC assays could be useful for routine purposes; however, for an accurate clinical data evaluation, their comparison versus a \u201cgold standard method\u201d is required

Homocysteine metabolism in children and adolescents with epidermolysis bullosa

Background: Epidermolysis bullosa (EB) belongs to a family of rare heterogeneous, genetic disorders characterized by blistering of the skin and mucous membranes in response to minor mechanical trauma. The involvement of the oral mucosa and oesophagus stenosis is suggested to be responsible for severe nutritional deficiencies, but few studies have till now considered this aspect. This observational study aimed to evaluate homocysteine status in children and adolescents with EB by assessing total plasma homocysteine (tHcy) and metabolically related vitamins (B6, B12, folate) concentrations. Methods: Twenty EB patients (12 M; age range 0.5-19 years) were evaluated for: plasma tHcy, serum B12 and holotranscobalamin (HoloTC, the active fraction of B12), serum and erythrocyte folate (s-F and Ery-F, respectively), plasma B6 and serum high sensitive C-reactive-protein (hsCRP) levels. Clinical severity was also evaluated through the Birmingham Epidermolysis Bullosa Severity (BEBS) score. A sex and age well-matched population was also enrolled. Results: EB patients showed tHcy levels higher (p = 0.04) and B6 levels lower (p = 0.03) than controls. B12, HoloTC, s-F and ery-F concentrations did not differ between patients and controls. Multiple linear regression analysis showed that tHcy levels were independent of the metabolically related vitamins levels. In addition, serum hsCRP levels were higher in EB patients than in controls (p = 0.003) and correlated negatively with B6 concentrations (r = -0.6; p = 0.009). BEBS score correlated negatively with HoloTC (p = 0.022) and B6 (p = 0.005) levels and positively with age (p = 0.031) and hsCRP levels (p < 0.001). Conclusions: The assessment of tHcy and metabolically related vitamin levels describes an important aspect of EB patients' nutritional status which can result essential for their long term care. Monitoring B6 levels in EB patients could be particularly important in order to prevent several complications associated with B6 deficiency and to avoid a B6 excess which sustains an inflammatory condition

Immunosuppressive drugs in whole blood : validation of a commercially available LC-MS/MS kit and comparison with immunochemical assays

RATIONALE: In the determination of immunosuppressive drugs cyclosporine A (CSA), tacrolimus (TARO), sirolimus (SIRO), and everolimus (EVE) in whole blood there is an open debate about which is the best assay between immunochemistry and liquid chromatography/tandem mass spectrometry (LC/MS/MS). This work is aimed to explore this topic, focusing on the use of updated assays and the analysis of a large number of samples. METHODS: A certified in vitro diagnostic kit coupled with a medical device LC/MS/MS was validated and applied to the analysis of 1192 blood samples of patients treated with immunosuppressive drugs. The results were compared with those obtained by immunoassays. RESULTS: The LC/MS/MS approach was found to provide linear, stable, precise, and accurate results, with lower limits of quantification of 12.5, 1.1, 1.2, and 1.2 \u3bcg/L for CSA, TACRO, SIRO, and EVE, respectively. With this method 80 samples were analysed and reported within a single work shift. A correlation was observed between the LC/MS/MS and immunoassay data, with Spearman correlation coefficients of 0.980 (n = 260) for CSA, 0.836 for TACRO (n = 562), 0.898 for SIRO (n = 113), and 0.904 for EVE (n = 257). Passing-Bablock regression showed the presence of constant and proportional biases for most of the drugs. A Blond-Altman graph showed differences between the assays, with immunoassays generally overestimating the drugs. CONCLUSIONS: The LC/MS/MS certified kit was validated for the detection of immunosuppressant drugs in whole blood and it provided a high-throughput method that is consistent with the requirements of clinical laboratories. The comparison of patient data between LC/MS/MS and up-dated immunoassays shows that a significant discrepancy still exists, especially for CSA and SIRO, confirming the greater specificity associated with use of the LC/MS/MS assay