Rachele De Giuseppe

Metformin overdose, but not lactic acidosis per se, inhibits oxygen consumption in pigs

IntroductionHepatic mitochondrial dysfunction may play a critical role in the pathogenesis of metformin-induced lactic acidosis. However, patients with severe metformin intoxication may have a 30 to 60% decrease in their global oxygen consumption, as for generalized inhibition of mitochondrial respiration. We developed a pig model of severe metformin intoxication to validate this clinical finding and assess mitochondrial function in liver and other tissues.MethodsTwenty healthy pigs were sedated and mechanically ventilated. Ten were infused with a large dose of metformin (4 to 8 g) and five were not (sham controls). Five others were infused with lactic acid to clarify whether lactic acidosis per se diminishes global oxygen use. Arterial pH, lactatemia, global oxygen consumption (VO2) (metabolic module) and delivery (DO2) (cardiac output by thermodilution) were monitored for nine hours. Oxygen extraction was computed as VO2/DO2. Activities of the main components of the mitochondrial respiratory chain (complex I, II and III, and IV) were measured with spectrophotometry (and expressed relative to citrate synthase activity) in heart, kidney, liver, skeletal muscle and platelets taken at the end of the study.ResultsPigs infused with metformin (6 ± 2 g; final serum drug level 77 ± 45 mg/L) progressively developed lactic acidosis (final arterial pH 6.93 ± 0.24 and lactate 18 ± 7 mmol/L, P < 0.001 for both). Their VO2 declined over time (from 115 ± 34 to 71 ± 30 ml/min, P < 0.001) despite grossly preserved DO2 (from 269 ± 68 to 239 ± 51 ml/min, P = 0.58). Oxygen extraction accordingly fell from 43 ± 10 to 30 ± 10% (P = 0.008). None of these changes occurred in either sham controls or pigs infused with lactic acid (final arterial pH 6.86 ± 0.16 and lactate 22 ± 3 mmol/L). Metformin intoxication was associated with inhibition of complex I in the liver (P < 0.001), heart (P < 0.001), kidney (P = 0.003), skeletal muscle (P = 0.012) and platelets (P = 0.053). The activity of complex II and III diminished in the liver (P < 0.001), heart (P < 0.001) and kidney (P < 0.005) while that of complex IV declined in the heart (P < 0.001).ConclusionsMetformin intoxication induces lactic acidosis, inhibits global oxygen consumption and causes mitochondrial dysfunction in liver and other tissues. Lactic acidosis per se does not decrease whole-body respiration.

Determinants of oxidative stress related to gender: relevance of age and smoking habit.

Abstract Background: Magnitude and major causes of oxidative stress may be different between sexes, although limitedly addressed in clinical studies with controversial results. The present study aimed to determine whether any gender-related difference exists concerning oxidative stress in a population of 332 subjects of both sexes, in a wide age range, with and without cigarette smoking habit. Methods: The Oxidative-INDEX was calculated after evaluation of serum hydroperoxides (ROMs) and total antioxidant capacity (OXY) by means of commercial kits (d-ROMs and Oxy-adsorbent Tests, Diacron, Italy) subtracting the OXY standardized variable from the ROMs standardized variable. Results: The Oxidative-INDEX resulted higher in women with respect to men (p<0.001), in smokers (p<0.01) than in non-smokers, and correlated with cigarette number (p<0.01), age (p<0.001), and post-menopausal status (p<0.001). The multivariate analysis identified age, high blood pressure, and smoking habit as factors independently associated with the Oxidative-INDEX in men, whereas cigarette smoking and age represented the independent risk factors for an elevated oxidative stress status in women. Conclusions: Gender-based differences in oxidative stress levels may provide a biochemical basis for the epidemiologic differences in the disease susceptibility between sexes, and suggest different strategies for risk assessment, diagnosis, and treatment specifically targeted to men and women.

Determination of serum holotranscobalamin concentrations with the AxSYM active B12 assay: cut-off point evaluation in the clinical laboratory

Abstract Background: A reliable early marker is required for diagnosis of cobalamin deficiency. We calculated an appropriate holotranscobalamin (HoloTC) cut-off point for identifying cobalamin deficiency using an immunoenzymatic assay. Methods: Determination of the cut-off threshold and correlation between HoloTC and the other diagnostic parameters routinely used for vitamin B12 deficiency [total vitamin B12 (tB12), folate, homocysteine] were measured in 250 routine blood specimens from 107 men (mean age 59.0±18.8 years) and 143 women (mean age 54.2±23.1 years). The inclusion criterion was serum tB12 concentration ≤221 pmol/L. Results: Analytical performance results agreed with those reported by others. A weak correlation (R=0.42) was found between HoloTC and tB12. A 40 pmol/L cut-off threshold was chosen for HoloTC and the associated sensitivity and specificity was 0.86 and 0.66, respectively. Out of 250 tested samples, 126 showed tB12 concentrations 139–221 pmol/L (gray zone, GZ) and 124 had tB12 concentrations <139 pmol/L (low, L). Values less than the cut-off for HoloTC were present in 68.2% and 37.9% of cases in the GZ and L group, respectively (p<0.01), and in 53.2% of subjects. Conclusions: Our results confirmed the analytical reliability of the AxSYM HoloTC assay. The method is adequate for routine use and a cut-off threshold of 40 pmol/L is appropriate for assessing cobalamin deficiency in populations with reduced tB12 values. Clin Chem Lab Med 2010;48:249–53.

A biomarker of oxidative stress as a nontraditional risk factor in obese subjects

BACKGROUND Oxidative stress has been postulated as an additive factor linking obesity to cardiovascular disease. MATERIALS & METHODS Derivatives of reactive oxygen species metabolites (d-ROMs) were measured in 136 obese (42 males, 94 females; mean age: 47 ± 12 years; BMI: 36 ± 5 kg/m(2)) and in 306 over- and normal-weight subjects (112 males, 194 females; age: 47 ± 12 years; BMI: 24 ± 3 kg/m(2)). RESULTS d-ROMs levels were higher in obese than in over- and normal-weight subjects (395 ± 104 vs 362 ± 102 and 351 ± 84 arbitrary units (AU); p < 0.001), in women than males (390 ± 104 vs 327 ± 68 AU; p < 0.001), in subjects with than those without hypertension (390 ± 103 vs 360 ± 95 AU; p < 0.01) and in smokers than former and nonsmokers (380 ± 97 vs 358 ± 97 AU; p < 0.05). A positive correlation was found between d-ROMs and BMI (r = 0.25; p < 0.001) and age (r = 0.13; p < 0.01). Levels of d-ROM (>75th percentile: 420 AU) remained as an independent obesity predictor (odds ratio: 2.5; p < 0.001) in women. Continuous variables are reported as mean ± standard deviation. CONCLUSION d-ROMs are a powerful obesity predictor, and could represent a reliable tool in obesity and cardiovascular risk evaluation, especially in women.

Efficacy of chelation therapy to remove aluminium intoxication

There is a distinct correlation between aluminium (Al) intoxication and neurodegenerative diseases (ND). We demonstrated how patients affected by ND showing Al intoxication benefit from short-term treatment with calcium disodium ethylene diamine tetraacetic acid (EDTA) (chelation therapy). Such therapy further improved through daily treatment with the antioxidant Cellfood. In the present study we examined the efficacy of long-term treatment, using both EDTA and Cellfood. Slow intravenous treatment with the chelating agent EDTA (2 g/10 mL diluted in 500 mL physiological saline administered in 2 h) (chelation test) removed Al, which was detected (using inductively coupled plasma mass spectrometry) in urine samples collected from patients over 12 h. Patients that revealed Al intoxication (expressed in μg per g creatinine) underwent EDTA chelation therapy once a week for ten weeks, then once every two weeks for a further six or twelve months. At the end of treatment (a total of 22 or 34 chelation therapies, respectively), associated with daily assumption of Cellfood, Al levels in the urine samples were analysed. In addition, the following blood parameters were determined: homocysteine, vitamin B12, and folate, as well as the oxidative status e.g. reactive oxygen species (ROS), total antioxidant capacity (TAC), oxidized LDL (oxLDL), and glutathione. Our results showed that Al intoxication reduced significantly following EDTA and Cellfood treatment, and clinical symptoms improved. After treatment, ROS, oxLDL, and homocysteine decreased significantly, whereas vitamin B12, folate and TAC improved significantly. In conclusion, our data show the efficacy of chelation therapy associated with Cellfood in subjects affected by Al intoxication who have developed ND.

Thrombin generation in patients with idiopathic sudden sensorineural hearing loss

INTRODUCTION The pathogenesis of idiopathic sudden sensorineural hearing loss (ISSNHL) is still unknown. Systemic hemostasis derangement causing local vascular occlusion might be one of the pathogenetic mechanisms. MATERIAL AND METHODS Forty-one patients with ISSNHL and 48 healthy subjects were investigated. We measured thrombin generation in the presence or absence of thrombomodulin in platelet-poor or platelet-rich plasma by means of a home-made method based on calibrated automated thrombin generation, which should mimic much more closely than any other conventional coagulation test the balance of coagulation operating in vivo. DNA analyses for the most common prothrombotic genotypes such as factor V Leiden, prothrombin G20210A, MTHFR or platelet GPIIIa A1/A2 were also carried out in patients and controls. RESULTS Patients generated as much thrombin as controls both in platelet-rich and platelet-poor plasma and the frequency of the most common prothrombotic genotypes were similar in patients and controls. CONCLUSIONS The results suggest that the pathogenesis of ISSNHL is not due to systemic blood hypercoagulability. Other culprits such as local vascular abnormalities, viral infections, immune-mediated mechanisms or abnormalities of inner ear and central nervous system should be advocated to explain ISSNHL.

Association of a history of childhood-onset obesity and dieting with eating disorders

ABSTRACT This was a retrospective, observational chart review conducted on a convenience sample of 537 outpatients, aged 16–60 years, referred to an Italian Dietetic and Nutrition University Center. The study aimed to look at the association between a history of childhood obesity and dieting behaviors with development of eating disorders (EDs) at a later age. Subjects with a history of EDs (n = 118), assessed using both self-report and health records, were compared with those with no EDs (n = 419), who were attending the clinic mainly for primary prevention of metabolic and cardiovascular risk. Logistic regression analysis was performed to assess the association of childhood-onset obesity with development of an ED at a later age. Childhood-onset obesity, gender, maternal history of eating disorders, and dieting were associated with a positive history of EDs at a later age (p < .05). It is important to raise professional awareness of early symptoms of EDs in children with a history of obesity and treat them accordingly.

An Encapsulated Juice Powder Concentrate Improves Markers of Pulmonary Function and Cardiovascular Risk Factors in Heavy Smokers

Objective: Cigarette smoking is associated with reduced pulmonary function and increased risk factors for cardiovascular disease. This randomized placebo-controlled double-blind study evaluated the effects of two different combinations of mixed fruit and vegetable juice powder concentrate (Juice Plus+, NSA, Collierville, TN) on heavy smokers. Methods: At baseline (T 0) and after 3 months’ supplementation (T 1), pulmonary function parameters and cardiovascular risk factors—that is, plasma total homocysteine (tHcy) with related B vitamins and cysteine (tCys) concentrations—were assessed in 75 apparently healthy smokers (aged 49.2 ± 10.6 years, >20 cigarettes/d, duration ≥10 years) randomized into 3 groups: placebo (P), fruit/vegetable (FV) and fruit/vegetable/berry (FVB). Results: T 0: most smokers showed abnormalities in tHcy and tCys concentrations. T 1: respiratory function was unchanged in P and slightly, but not significantly, improved in FV, whereas FVB showed a significant improvement in forced expiratory flow at 25% (FEF25; p < 0.0001 vs P and FV) and significant improvement in CO diffusion lung/alveolar volume (DLCO/VA). FV and FVB (50%) showed significant reduction in tHcy and tCys compared to T 0 ( p < 0.0001) and P ( p < 0.0001). Conclusions: At T 1, both supplemented groups, but to a greater extent the FVB group, showed improvements in some pulmonary parameters, cardiovascular risk factors, and folate status. The beneficial effects of Juice Plus+ supplementation could potentially help smokers, even if smoking cessation is advisable.

Oxidative status in treatment-naïve essential thrombocythemia: a pilot study in a single center

Oxidative stress (OS), due to pro‐oxidant species [reactive oxygen species (ROS)] excess not counterbalanced by endogenous antioxidant molecules [e.g., reduced glutathione (GSH)], is involved in the pathogenesis of human cancers, but few data are available on essential thrombocythemia (ET). This study aims to investigate OS in ET off‐therapy patients. Thirty ET treatment‐naïve patients were compared with 26 age‐matched and gender‐matched controls. Serum ROS, urinary 8‐hydroxydeoxyguanosine, full blood GSH levels, and reduced/oxidized GSH ratio (GSH/GSSG) were measured. Data were adjusted for gender, age, JAK2 mutational status, smoking, dyslipidemia, or hypercholesterolemia requiring drug therapy, antiplatelet therapy, treatment with acetylsalicylic acid, high‐sensitive C‐reactive protein levels, and absolute monocyte count. ROS and GSH levels were increased in both patients and controls. Patients showed increased GSSG (p = 0.05), reduced GSH/GSSG ratio (p = 0.08), and similar 8‐hydroxydeoxyguanosine levels when compared with controls. No differences in OS parameters were found between JAK2‐positive and JAK2‐negative patients. Confounding factors did not modify the results. Our study suggests an OS condition in a cohort of treatment‐naïve ET patients, not associated with JAK2 mutational status or with chronic inflammation situation. GSH/GSSG ratio, altered in ET patients because of increased GSSG levels, showed the presence of higher GSH levels in ET than controls as a possible compensatory mechanism of an excess of pro‐oxidant production. Copyright

Analytical performance and method comparison study of the total homocysteine immunoassay on the AIA 600II analyser

*Corresponding author: Cristina Novembrino, Laboratory of Clinical Chemistry and Microbiology, Fondazione IRCCS C a Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20122 Milano, Italy, Phone: + 39 0255033473, Fax: + 39 0255034571, E-mail: cristina.novembrino@policlinico.mi.it Rachele De Giuseppe, Claudia De Vita and Fabrizia Bamonti: Department of Biomedical, Surgical and Dental Sciences, University of Milan; Department of Hematology-Oncology and BMT Unit, Fondazione IRCCS C a Granda Ospedale Maggiore Policlinico, Milan, Italy Federica de Liso, Erminio Torresani and Rita Maiavacca: Laboratory of Clinical Chemistry and Microbiology, Fondazione IRCCS C a Granda Ospedale Maggiore Policlinico, Milan, Italy Agostino Cortelezzi: Department of Clinical Sciences and Community Health, University of Milan; Department of HematologyOncology and BMT Unit, Fondazione IRCCS C a Granda Ospedale Maggiore Policlinico, Milan, Italy Iris Romero and Paola Bellati: Marketing & Scientific Department, Tosoh Bioscience, Turin, Italy