Gabriele Grossi

Serum steroid profiling by isotopic dilution-liquid chromatography–mass spectrometry: Comparison with current immunoassays and reference intervals in healthy adults

BACKGROUND The simultaneous, rapid and reliable measurement of a wide steroid panel is a powerful tool to unravel physiological and pathological hormone status. Clinical laboratories are currently dominated by high-throughput immunoassays, but these methods lack specificity due to cross-reactivity and matrix interferences. We developed and validated an isotopic dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method for the simultaneous measurement of cortisol, corticosterone, 11deoxycortisol, androstenedione, deoxycorticosterone (DOC), testosterone, 17OHprogesterone, dehydroepiandrosterone (DHEA) and progesterone in serum, and compared it to routine immunoassays employed in our laboratory. We also established adult reference intervals in 416 healthy subjects. METHODS 0.9 ml of serum were spiked with labelled internal standards (IS) and extracted on C18 cartridges. Eluate was injected into a two-dimensional LC-system, purified in a perfusion column and separated on a C8 column during a 21 min gradient run. Analytes were revealed by atmospheric pressure chemical ionization (APCI) followed by multiple reaction monitoring (MRM) analysis. RESULTS Of the four immunoassays compared with the ID-LC-MS/MS method, only the results of ElecsysE170 for cortisol, testosterone in males and progesterone>1 ng/ml were in agreement with ID-LC-MS/MS. ElecsysE170 for testosterone in females and progesterone<1 ng/ml, Immulite2000 for androstenedione, DSL-9000 for DHEA and 17OHP Bridge for 17OHprogesterone, respectively, showed poor agreement. Reference intervals and steroid age and fertility related fluctuations were established. CONCLUSION Our ID-LC-MS/MS method proved to be reliable and sensitive in revealing steroid circulating concentrations in adults and in highlighting the limits of routine immunoassays at low concentrations.

Estimation of reference intervals of five endocannabinoids and endocannabinoid related compounds in human plasma by two dimensional-LC/MS/MS

The elucidation of the role of endocannabinoids in physiological and pathological conditions and the transferability of the importance of these mediators from basic evidence into clinical practice is still hampered by the indefiniteness of their circulating reference intervals. In this work, we developed and validated a two-dimensional LC/MS/MS method for the simultaneous measurement of plasma endocannabinoids and related compounds such as arachidonoyl-ethanolamide, palmitoyl-ethanolamide, and oleoyl-ethanolamide, belonging to the N-acyl-ethanolamide (NAE) family, and 2-arachidonoyl-glycerol and its inactive isomer 1-arachidonoyl-glycerol from the monoacyl-glycerol (MAG) family. We found that several pitfalls in the endocannabinoid measurement may occur, from blood withdrawal to plasma processing. Plasma extraction with toluene followed by on-line purification was chosen, allowing high-throughput and reliability. We estimated gender-specific reference intervals on 121 healthy normal weight subjects fulfilling rigorous anthropometric and hematic criteria. We observed no gender differences for NAEs, whereas significantly higher MAG levels were found in males compared with females. MAGs also significantly correlated with triglycerides. NAEs increased with age in females, and arachidonoyl-ethanolamide correlated with adiposity and metabolic parameters in females. This work paves the way to the establishment of definitive reference intervals for circulating endocannabinoids to help physicians move from the speculative research field into the clinical field.

Statin therapy decreases serum levels of high-sensitivity C-reactive protein and tumor necrosis factor-α in HIV-infected patients treated with ritonavir-boosted protease inhibitors.

Abstract Background: Statins are lipid-lowering drugs that exhibit anti-inflammatory and immune-modulatory properties, leading to a reduction of serum levels of C-reactive protein (CRP) in the general population. Objective: Because very limited data are available today, our objective was to assess the lipid-lowering effects of statins and their capacity to decrease selected soluble markers of inflammation in HIV-infected patients. Methods: Retrospective cohort study of HIV-infected adult patients with hypercholesterolemia who were receiving a stable antiretroviral regimen including a ritonavir-boosted protease inhibitor and who started a lipid-lowering therapy with rosuvastatin (10 mg daily), atorvastatin (10 mg daily), or pravastatin (40 mg daily) and were followed-up for at least 12 months. One hundred and fifty-one patients were enrolled in the study: 51 in the rosuvastatin group, 47 in the atorvastatin group, and 53 in the pravastatin group. The primary observation was change in plasma lipid levels and serum markers of inflammation (high-sensitivity C-reactive protein [hsCRP], interleukin-6 [IL-6], and tumor necrosis factor-α [TNF- α]), while secondary observations include immunovirological parameters and safety profile of statins. Results: One year after starting the statin therapy, patients treated with rosuvastatin had significantly greater decreases in total cholesterol and LDL cholesterol than subjects on atorvastatin or pravastatin. All statins led to a similar, significant reduction in serum levels of hsCRP and TNF-α, without correlation between biomarkers and lipid values, and toxicity rates were similar for all 3 statins. Conclusion: Our findings suggest that rosuvastatin has a significantly greater lipid-lowering effect than atorvastatin or pravastatin, but all 3 statins exert a similar effect in lowering markers of inflammation as hsCRP and TNF-α.

5-Methyltetrahydrofolate Administration Is Associated with Prolonged Survival and Reduced Inflammation in ESRD Patients

BACKGROUND Hemodialysis (HD) patients have a greatly increased risk of cardiovascular morbidity and mortality. For this reason, attempts are often made to normalize hyperhomocysteinemia. This randomized prospective study sought to determine which risk factors are predictors of mortality and whether high doses of folates or 5-methyltetrahydrofolate (5-MTHF) could improve hyperhomocysteinemia and survival in HD patients. METHODS 341 patients were divided into two groups: group A was treated with 50 mg i.v. 5-MTHF, and group B was treated with 5 mg/day oral folic acid. Both groups received i.v. vitamin B(6) and B(12). By dividing patients into C-reactive protein (CRP) quartiles, group A had the highest survival for CRP <12 mg/l, whereas no survival difference was found for group B. CRP was the only predictive risk factor for death (RR 1.17, range 1.04-1.30, p = 0.02). Dialysis age, hyperhomocysteinemia, methylenetetrahydrofolate reductase polymorphism, albumin, lipoprotein (a) and folate did not influence mortality risk. Survival in group A was higher than that in group B, namely 36.2 +/- 20.9 vs. 26.1 +/- 22.2 months (p = 0.003). RESULTS Our results suggest that CRP, but not hyperhomocysteinemia, is the main risk factor for mortality in HD patients receiving vitamin supplements. Intravenous 5-MTHF seems to improve survival in HD patients independent from homocysteine lowering.

EVIDENCE FOR A HYPOTHALAMIC ALTERATION OF CATECHOLAMINE METABOLISM IN POLYCYSTIC OVARY SYNDROME

The role of brain catecholamine (CA) activity in the neuroendocrine regulation of the GnRH‐LH system in polycystic ovary syndrome (PCO) was investigated by high‐performance liquid chromatography (HPLC) with electrochemical detector. We measured urinary dopamine (DA), noradrenaline (NA), adrenaline (A), vanillylmandelic acid (VMA), homovanillic acid (HVA), 3,4‐dihydr‐oxyphenylacetic acid (DOPAC) and total 3‐methoxy‐4‐hydroxyphenylglycol (MHPG) levels in a group of 12 women with PCO before and during peripheral dopa‐decarboxylase blockade, by carbidopa. HVA and DOPAC concentrations were significantly lower (P<0001 and P<0‐005, respectively) in PCO patients compared with twelve control subjects in early follicular phase, whereas total MHPG concentrations and MHPG/VMA ratio were significantly higher (P< 0‐005) in PCO patients. Moreover, HVA and DOPAC concentrations in PCO patients were similar to those of the control subjects in preovulatory phase, while MHPG concentrations remained higher in PCO patients (P<0‐01). DA, NA, A and VMA concentrations were similar to those of control subjects in both phases of the cycle. During carbidopa administration the concentrations of all urinary CAs and metabolites were unchanged, except those of DA which dropped markedly (P<0‐001). These data suggest that (1) an altered central catecholamine metabolism consisting of DA deficiency and NA excess is present in PCO, and (2) the site of DA deficiency may be located in the hypothalamus.

Lopinavir/ritonavir trough concentrations with the tablet formulation in HIV-1-infected women during the third trimester of pregnancy

Abstract Objectives: An observational, open-label study was performed to assess changes of lopinavir/ritonavir plasma concentrations during pregnancy. Methods: Adult HIV-1-infected women during the third trimester of pregnancy and on stable antiretroviral treatment including zidovudine/lamivudine plus lopinavir/ritonavir tablets (400/100 mg twice daily) were asked to participate. This group was compared with a group of non-pregnant HIV-1-infected women receiving the same antiretroviral regimen. The trough plasma concentration (Ctrough) of lopinavir and ritonavir was assessed at steady-state by a validated high-performance liquid chromatography (HPLC)-tandem mass spectrometry method. Results: A total of 41 HIV-positive female patients were enrolled in the study, with a median age of 28 y (range 20–37 y). These patients were stratified into 2 groups: 21 women in the third trimester of pregnancy (group A) and 20 non-pregnant women (group B). The geometric mean (95% confidence interval (CI)) plasma Ctrough of lopinavir was 4205 (2418–6896) ng/ml in group A and 5098 (3187–8084) ng/ml in group B. The reduction in lopinavir plasma levels observed in group A was not significant (geometric mean ratio 0.87, 95% CI 0.62–1.32; p = 0.411). No correlation was found between lopinavir plasma levels and adverse events (such as diarrhoea and hyperlipidaemia) or immunological parameters of HIV disease, and no changes in plasma HIV viral load were reported. Conclusion: In this study, a slight but not significant decrease in the plasma lopinavir Ctrough was found during the third trimester of pregnancy, suggesting that standard dosing of the tablet formulation is also appropriate during the later stages of pregnancy.

Vitamin A and vitamin E isoforms stability and peroxidation potential of all-in-one admixtures for parenteral nutrition.

BACKGROUND In all-in-one admixtures (AIOs), vitamins can be degraded and lipid can be peroxidized by light exposure, oxygen action, and multiple chemical interactions. AIM We investigated the impact of three commercial lipid emulsions and two multivitamin preparations on vitamin A and vitamin E chemical stability and lipid peroxidation potential of AIOs. METHODS A soybean oil (Soy), soybean/medium-chain triacylglycerol oil (MCT), and olive/soybean oil (Olive)-based emulsion (all 20%), and a lyophilized (Lyo) and emulsified (Emu) multivitamin compounds, were tested. Two AIOs for each lipid emulsion were prepared, the former with Lyo and the latter with Emu. The concentrations of retinol palmitate, alpha-gamma-delta-tocopherol, and malondialdehyde were analyzed in AIOs, immediately (T0) and 24 hours (T24) after compounding. RESULTS Retinol palmitate, and alpha- and gamma-tocopherol were more stable in MCT-AIOs than in both Soy-AIOs and Olive-AIOs (p < 0.013; p < 0.001 respectively). Furthermore alpha-tocopherol was more stable in Lyo-AIOs than in Emu-AIOs (p < 0.004). Malondialdehyde (MDA) increased differently among the admixtures; however the concentrations were similar in all AIOs at T24. CONCLUSIONS The differences in retinol palmitate stability were due both to lipid emulsions per se and to interaction between lipid emulsions and multivitamin preparations. The alpha-gamma-tocopherol stability depended on both lipid emulsions and multivitamin preparations. In tested AIOs there was a different degradation rate of fat-soluble vitamins to keep the same lipid peroxidation level, since MDA concentrations at T24 were similar among AIOs.

Phytosterols and Lack of Occurrence of Cholestasis in Rats Nourished Parenterally or Orally

Intravenous lipid emulsions (ILEs) have been marketed to infuse fat within total parenteral nutrition (TPN) in order to prevent essential fatty acid deficiency. Only recently, ILEs have been recognized to have therapeutic effects in gastrointestinal, cardiovascular, pulmonary, oncologic, autoimmune, and critical care diseases. At the same time, toxic substances such as phytosterols have been found in ILEs. Phytosterols have been related to a TPN-associated complication defined parenteral nutrition-associated cholestasis (PNAC) (1-5).

Changes in Brain Catecholamine Metabolism during Bromocriptine Treatment in Polycystic Ovary Syndrome

The role of dopaminomimetic drugs on the brain catecholamine metabolism in the neuroendocrine regulation of the polycystic ovary syndrome (PCO) was investigated. We measured, besides peptide hormones and sex steroids, urinary dopamine (DA), norepinephrine, epinephrine, vanillylmandelic acid, homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC) and total 3-methoxy-4-hydroxyphenylglycol (MHPG) levels by high-performance liquid chromatography with electrochemical detector in 10 women with PCO before and during long-term bromocriptine (BRC) administration. HVA and DOPAC concentrations were significantly lower (p < 0.001) in PCO patients compared with 12 control subjects in the early follicular phase, whereas MHPG concentrations were significantly higher (p < 0.01) in PCO patients. During BRC administration, HVA, DOPAC and MHPG levels increased significantly (p < 0.01 for HVA and DOPAC, and p < 0.05) for MHPG), prolactin levels dropped markedly (p < 0.01), whereas luteinizing hormone levels did not change (p = NS). These data show (1) a reduced DA activity in PCO which may be normalizable under BRC treatment, but also (2) no major effects of DA metabolism on the inappropriate gonadotropin secretion of the syndrome.

Evidence for Pathological Reduction in Brain Dopamine Metabolism in Idiopathic Hyperprolactinemia

The role of brain catecholamine activity in the neuroendocrine regulation of the dopamine-PRL system in idiopathic hyperprolactinemia was investigated by high-performance liquid chromatography with electrochemical detector. We measured urinary dopamine, norepinephrine, epinephrine, vanillylmandelic acid, homovanillic acid, 3,4-dihydroxyphenylacetic acid and total 3-methoxy-4-hydroxyphenylglycol levels in 12 women with idiopathic hyperprolactinemia before and during either peripheral dopa-decarboxylase blockade, by carbidopa, or dopamine beta-hydroxylase blockade, by disulfiram. Homovanillic acid and 3,4-dihydroxyphenylacetic acid concentrations were significantly lower (p less than 0.001 and p less than 0.005, respectively) in patients with idiopathic hyperprolactinemia compared with those in 12 control subjects in the early follicular phase, whereas they were similar to those in the control subjects in the pre-ovulatory phase. Dopamine, norepinephrine, epinephrine, vanillylmandelic acid and 3-methoxy-4-hydroxyphenylglycol concentrations were similar to those of the control subjects in both phases of the cycle. During carbidopa administration the levels of all urinary catecholamines and metabolites were unchanged, except that of dopamine which dropped remarkably (p less than 0.001). During disulfiram administration dopamine, homovanillic acid and 3,4-dihydroxyphenylacetic acid concentrations increased (p less than 0.05, p less than 0.001 and p less than 0.005, respectively) and those of norepinephrine, vanillylmandelic acid and 3-methoxy-4-hydroxyphenylglycol decreased (p less than 0.05, p less than 0.001 and p less than 0.005, respectively), whereas epinephrine levels remained unaltered. These data support the existence of a quantitatively reduced brain dopamine activity in idiopathic hyperprolactinemia.