Ruolo dell'ossido nitrico sul rilascio dell'attivatore tissutale del plasminogeno nei soggetti normotesi e nei pazienti ipertesi

L’endotelio vascolare gioca un ruolo primario nella modulazione di molte funzioni importanti del sistema circolatorio inclusi il tono vascolare e la fibrinolisi. La principale sostanza implicata in queste funzioni è l’NO, prodotto dalle cellule endoteliali ad opera dell’enzima NO-sintetasi dal catabolismo dell’L-arginina. In presenza dei maggiori fattori di rischio cardiovascolare, fra cui l’ipertensione, è dimostrata una ridotta produzione e secrezione di NO, che si ripercuote negativamente sulla vasomotricità e sulle proprietà antitrombotiche dell’endotelio. Scopo della presente tesi è di valutare il possibile ruolo dell’ossido nitrico nella modulazione del rilascio del fattore tissutale del plasminogeno (t-PA) nel microcircolo dell’avambraccio di soggetti normotesi e di pazienti ipertesi. Nei volontari sani e nei pazienti con ipertensione essenziale abbiamo studiato il rilascio locale di t-PA e le modificazioni del flusso a livello dell’avambraccio, mediante pletismografia strain-gauge, indotte dalla somministrazione intrarteriosa di acetilcolina e di nitroprussiato di sodio, rispettivamente un agonista endotelio-dipendente ed endotelio indipendente. L’infusione di acetilcolina è stata anche ripetuta durante infusione intrarteriosa dell’inibitore dell’NO sintetasi N-monometil-L-arginina. Nei soggetti normotesi, la risposta vasodilatante all’acetilcolina ha determinato un significativo incremento, dose dipendente, del rilascio di t-PA nell’avambraccio. In presenza di N-monometil-L-arginina, che ha significativamente ridotto l’effetto vasodilatante dell’acetilcolina, il rilascio di t-PA, sia basale che indotto da acetilcolina, è risultato ridotto. Nei pazienti con ipertensione essenziale, la vasodilatazione mediata dall’acetilcolina, ridotta rispetto ai controlli, non ha determinato un significativo rilascio di t-PA. In questi pazienti, la N-monometil-L-arginina non ha modificato né la risposta vasodilatante dell’acetilcolina né il rilascio basale di t-PA, sia basale che indotto. I risultati di questa tesi dimostrano che sia la secrezione tonica di NO che quella indotta dall’agonista endoteliale giocano un ruolo diretto nel rilascio di t-PA da parte delle cellule endoteliali. Nei pazienti ipertesi essenziali, caratterizzati da una ridotta disponibilità di NO, vi è anche associata una ridotta capacità di rilascio di t-PA, suggerendo così l’importanza della disponibilità di NO, che, quando ridotta, compromette sia la capacità vasomotoria che il rilascio di t-PA

Analytical evaluation of Radiometer ABL90 FLEX PLUS enzymatic creatinine assay

Background: The diagnosis of kidney disease strongly relies on accurate and reproducible measurements of creatinine, even when performed with point of care testing (POCT) devices. Therefore, this study aimed at performing a comprehensive evaluation of the analytical performance of a creatinine enzymatic assay on the Radiometer ABL90 FLEX PLUS. Methods: This analytical evaluation encompassed the assessment of intra-assay, inter-assay and total imprecision, along with linearity on routine lithium-heparin plasma samples. Method comparison was also carried out using results generated with Radiometer ABL90 FLEX PLUS in heparinized whole blood and those obtained in paired heparinized plasma with a reference enzymatic creatinine assay and a Jaffe method, both assayed on Roche Cobas c702. Results: The intra-assay imprecision of Radiometer ABL90 FLEX PLUS creatinine enzymatic assay was between 0.33\u20131.26%, the inter-assay imprecision between 0.64\u20131.78%, thus yielding a total imprecision of 0.79\u20131.99%. The linearity of the assay was excellent (r=1.000; P<0.001) in a range of plasma creatinine concentrations between 47 and 445 \ub5mol/L. An excellent correlation was found between creatinine measured on heparinized whole blood using Radiometer ABL90 FLEX PLUS enzymatic assay and plasma creatinine assayed on the same centrifuged samples using both Roche Cobas c702 creatinine enzymatic assay (r=0.99 and r=0.98; both P<0.001). Compared to both Roche Cobas assays the percent bias was 641% and the agreement at chronic kidney disease (CKD) diagnostic thresholds was 6594%. Conclusions: The results of this analytical evaluation confirm that Radiometer ABL90 FLEX PLUS creatinine enzymatic assay is at least as suitable as a conventional clinical chemistry enzymatic technique for routine and urgent diagnosis of kidney diseases

Blood sample quality using Greiner Bio-One HOLDEX\uae Single-Use Holder and VACUETTE\uae SAFELINK holder with male luer lock: a comparative study

Background: Hemolysis is the most frequent and potentially one of the most harmful causes of poor sample quality. Many strategies have been attempted for minimizing the risk of generating spurious hemolysis during blood collection, such as using the HOLDEX\uae single-use holder, which features a chamber that decelerates blood flow pressure before entering evacuated blood tubes. We have hence designed a study to establish whether the new VACUETTE\uae SAFELINK, which shares different structure but similar strategy affecting blood flow pressure, may ensure a comparable sample quality as using HOLDEX\uae single-use holder. Methods: A total number of 24 clinical chemistry, hematologic and hemostasis parameters were measured in paired blood samples collected from 30 healthy volunteers using either HOLDEX\uae single-use holder or VACUETTE\uae SAFELINK. Test results were compared with paired Student\u2019s t-test, Pearson\u2019s correlation and Bland-Altman plots. Results: All test results were non-significantly different in blood samples collected with HOLDEX\uae single-use holder or VACUETTE\uae SAFELINK except potassium, whose values were marginally higher in plasma collected with VACUETTE\uae SAFELINK. All Pearson\u2019s correlation coefficients were excellent except potassium, chloride and H-index. In this latter case, the correlation did not reach statistical significance. The percent bias of different parameters in samples collected with HOLDEX\uae single-use holder or VACUETTE\uae SAFELINK was minimal, comprised between 124.5% and +1.6%. In all cases the percent bias was comprised within the quality specifications tests. The rate of plasma samples with H-index >3 was eventually lower when blood was collected using SAFELINK than with HOLDEX\uae single use holder (odds ratio, 0.52; 95% confidence interval, 0.17\u20131.60). Conclusions: The results of this comparative study suggest that sample quality is thoughtfully comparable using HOLDEX\uae single-use holder and VACUETTE\uae SAFELINK, thus translating into the concept that VACUETTE\uae SAFELINK may also be an effective means for reducing spurious hemolysis, especially when drawing blood from catheters

Changes in cerebrospinal fluid balance of TNF and TNF receptors in naïve multiple sclerosis patients: early involvement in compartmentalised intrathecal inflammation

An imbalance of TNF signalling in the inflammatory milieu generated by meningeal immune cell infiltrates in the subarachnoid space in multiple sclerosis (MS), and its animal model may lead to increased cortical pathology. In order to explore whether this feature may be present from the early stages of MS and may be associated with the clinical outcome, the protein levels of TNF, sTNF-R1 and sTNF-R2 were assayed in CSF collected from 122 treatment-naive MS patients and 36 subjects with other neurological conditions at diagnosis. Potential correlations with other CSF cytokines/chemokines and with clinical and imaging parameters at diagnosis (T0) and after 2 years of follow-up (T24) were evaluated. Significantly increased levels of TNF (fold change: 7.739; p < 0.001), sTNF-R1 (fold change: 1.693; p < 0.001) and sTNF-R2 (fold change: 2.189; p < 0.001) were detected in CSF of MS patients compared to the control group at T0. Increased TNF levels in CSF were significantly (p < 0.01) associated with increased EDSS change (r = 0.43), relapses (r = 0.48) and the appearance of white matter lesions (r = 0.49). CSF levels of TNFR1 were associated with cortical lesion volume (r = 0.41) at T0, as well as with new cortical lesions (r = 0.56), whilst no correlation could be found between TNFR2 levels in CSF and clinical or MRI features. Combined correlation and pathway analysis (ingenuity) of the CSF protein pattern associated with TNF expression (encompassing elevated levels of BAFF, IFN-gamma, IL-1 beta, IL-10, IL-8, IL-16, CCL21, haptoglobin and fibrinogen) showed a particular relationship to the interaction between innate and adaptive immune response. The CSF sTNF-R1-associated pattern (encompassing high levels of CXCL13, TWEAK, LIGHT, IL-35, osteopontin, pentraxin-3, sCD163 and chitinase-3-L1) was mainly related to altered T cell and B cell signalling. Finally, the CSF TNFR2-associated pattern (encompassing high CSF levels of IFN-beta, IFN-lambda 2, sIL-6R alpha) was linked to Th cell differentiation and regulatory cytokine signalling. In conclusion, dysregulation of TNF and TNF-R1/2 pathways associates with specific clinical/MRI profiles and can be identified at a very early stage in MS patients, at the time of diagnosis, contributing to the prediction of the disease outcome

Vitamin D deficiency and pregnancy disorders

Vitamin D deficiency (VDD) is a global health care issue, with billion carrying deficiency or insufficiency around the world. This hormone plays a kaleidoscope of important roles throughout pregnancy, so that maintenance of an adequate vitamin D status is essential in this setting. Several studies, which have investigated vitamin D status in different populations of pregnant women, have convincingly reported high prevalence of vitamin D insufficiency, consistently higher than 50%. Although VDD developing during pregnancy has been associated with some adverse maternal and pregnancy outcomes, especially gestational diabetes mellitus (GDM) and preeclampsia (PE), the risk estimated are considerably heterogeneous, which makes it challenging to define operative recommendations. The mean differences in serum 25-hydroxy- cholecalciferol [25(OH)D] between GDM and non-GDM pregnant women varies between 124.93 and 127.36 nmol/L, whilst that between pre-eclamptic and non-pre-eclamptic pregnant women is even wider, being comprised between 123.86 and 1214.53 nmol/L. It is hence still unclear whether assessment of vitamin D during pregnancy shall be recommended, as well as which dose of vitamin D shall be administered in pregnant women with VDD. Further studies shall be planned, which will need to be based on reliable quantification techniques [preferably liquid chromatography tandem mass spectrometry (LC-MS/MS)-based methods], but will also need to reduce the impact of many confounding factors such as ethnicity, sunlight exposure and sampling time

Can citrate plasma be used in exceptional circumstances for some clinical chemistry and immunochemistry tests?

Background The use of alternative sample matrices may be an advantageous perspective when the laboratory falls short of serum or lithium-heparin plasma for performing clinical chemistry and/or immunochemistry testing. This study was aimed at exploring whether some tests may be performed in citrate plasma as an alternative to lithium-heparin plasma. Methods Paired lithium-heparin and citrate plasma samples collected from 55 inpatients were analyzed on Roche Cobas 8000 for 28 different clinical chemistry and immunochemistry parameters. Data obtained in citrate plasma were adjusted for either the dilution factor or using an equation corresponding to the linear regression calculated by comparing unadjusted lithium-heparin and citrate plasma values. Results Except for magnesium (+17%) and sodium (+11%), unadjusted values of all remaining analytes were significantly lower in citrate than in lithium-heparin plasma, with bias ranging between -6.4% and -25.9%. The correlation between lithium-heparin and citrate plasma values was generally excellent (i.e. >0.90). The adjustment of citrate plasma values for the dilution factor (i.e. 1.1) was only effective in harmonizing the results of albumin and lipase, whilst the concentration of all other analytes remained significantly different between the two sample matrices. The adjustment of plasma citrate values using corrective formulas was instead effective in harmonizing all parameters, with no results remaining statistically different between the two sample matrices. Conclusions Citrate plasma may be used in exceptional circumstances for clinical chemistry and immunochemistry testing as a replacement for lithium-heparin plasma, provided that citrate plasma values are adjusted by using validated corrective equations

Updated overview on the interplay between obesity and COVID-19

The worldwide spread of coronavirus disease 2019 (COVID-19) has generated a global health crisis and more than a million deaths so far. Epidemiological and clinical characteristics of COVID-19 are increasingly reported, along with its potential relationship with overweight and/or obesity. Therefore, we aim here to review the current scientific literature on the impact of overweight and/or obesity among hospitalized patients who have developed severe or critical forms of COVID-19. Following PRISMA guidelines, our literature search identified over 300 scientific articles using the keywords "obesity" and "COVID-19", 22 of which were finally selected for reporting useful information on the association between overweight/obesity and disease severity. In particular, in 11 out of the 14 studies (79%) which evaluated the association between obesity and disease severity providing also a risk estimate (i.e., the odd ratio; OR), the OR value was constantly >2. Although the studies were found to be heterogeneous in terms of design, population, sample size and endpoints, in most cases a significant association was found between obesity and the risk of progressing to severe COVID-19 illness, intensive care unit admission and/or death. We can hence conclude that an increased body mass index shall be considered a negative prognostic factor in patients with COVID-19, and more aggressive prevention or treatment shall hence be reserved to overweight and/or obese patients

The challenges of diagnosing diabetes in childhood

Diabetes is one of the most prevalent diseases worldwide, whereby type 1 diabetes mellitus (T1DM) alone involves nearly 15 million patients. Although T1DM and type 2 diabetes mellitus (T2DM) are the most common types, there are other forms of diabetes which may remain often under-diagnosed, or that can be misdiagnosed as being T1DM or T2DM. After an initial diagnostic step, the differential diagnosis among T1DM, T2DM, Maturity-Onset Diabetes of the Young (MODY) and others forms has important implication for both therapeutic and behavioral decisions. Although the criteria used for diagnosing diabetes mellitus are well defined by the guidelines of the American Diabetes Association (ADA), no clear indications are provided on the optimal approach to be followed for classifying diabetes, especially in children. In this circumstance, both routine and genetic blood test may play a pivotal role. Therefore, the purpose of this article is to provide, through a narrative literature review, some elements that may aid accurate diagnosis and classification of diabetes in children and young people

Protective Effects of Statins Administration in European and North American Patients Infected with COVID-19: A Meta-analysis

Severe acute respiratory syndrome coronavirus 2 has spread rapidly throughout the world, becoming an overwhelming global health emergency. The array of injuries caused by this virus is broad and not limited to the respiratory system, but encompassing also extensive endothelial and systemic tissue damage. Since statins effectively improve endothelial function, these drugs may have beneficial effects in patients with coronavirus disease 2019 (COVID-19). Therefore, this investigation aimed to provide an updated overview on the interplay between statins and COVID-19, with particular focus on their potentially protective role against progression toward severe or critical illness and death. A systematic electronic search was performed in Scopus and PubMed up to present time. Data on statins use and COVID-19 outcomes especially in studies performed in Europe and North America were extracted and pooled. A total of seven studies met our inclusion criteria, totaling 2,398 patients (1,075 taking statins, i.e., 44.8%). Overall, statin usage in Western patients hospitalized with COVID-19 was associated with nearly 40% lower odds of progressing toward severe illness or death (odds ratio: 0.59; 95% confidence interval: 0.35-0.99). After excluding studies in which statin therapy was started during hospital admission, the beneficial effect of these drugs was magnified (odds ratio: 0.51; 95% confidence interval: 0.41-0.64). In conclusion, although randomized trials would be necessary to confirm these preliminary findings, current evidence would support a favorable effect of statins as adjuvant therapy in patients with COVID-19. Irrespective of these considerations, suspension of statin therapy seems highly unadvisable in COVID-19 patients

Analytical Evaluation of the New Beckman Coulter Access Procalcitonin (PCT) Chemiluminescent Immunoassay

This study was designed to evaluate the analytical performance of the recently commercialized Beckman Coulter Access procalcitonin (PCT) chemiluminescent test on the Access immunoassay system. The analytical assessment encompassed the estimation of limit of blank (LoB), limit of detection (LoD), functional sensitivity (i.e., PCT value with 6410% imprecision), linearity, imprecision and comparability of values with BRAHMS PCT-sensitive Kryptor. LoB, LoD and functional sensitivity were 0.002 \u3bcg/L, 0.003 \u3bcg/L and 0.003 \u3bcg/L, respectively. Intra-assay, inter-assay and total imprecision for plasma pools with low, medium and high PCT values were 1.8%-2.1%, 2.4%-3.7% and 3.1%-4.3%, respectively. The assay exhibited excellent linearity between 0.02 and 84.0 \u3bcg/L. Excellent correlation (r = 0.999; p < 0.001) and negligible bias (3.2%) were found by comparing values obtained in paired plasma samples with BRAHMS PCT-sensitive Kryptor. Diagnostic agreement at 0.5, 2.0 and 10 \u3bcg/L PCT values ranged between 98%-100%. The results of this study confirm that Access PCT displays excellent analytical performance and high comparability with BRAHMS PCT-sensitive Kryptor