Cadmium elicits alterations in mitochondrial morphology and functionality in C3H10T1/2Cl8 mouse embryonic fibroblasts.

BACKGROUND: Cadmium is a widespread carcinogen. We previously showed that the administration of low CdCl2 doses for 24 h to healthy C3H10T1/2Cl8 mouse embryonic fibroblast cell line at the beginning of Cell Transformation Assay (CTA), up regulates genes involved in metal scavenging and antioxidant defense, like metallothioneines, glutathione S-transferases and heat shock proteins. Still, although most cells thrive normally in the following weeks, malignancy is triggered by CdCl2 and leads to the appearance of foci of transformed cells at the end of the CTA. In this work we aim at elucidating the early metabolic deregulation induced by cadmium, underlying healthy cell transformation into malignant cells. METHODS: Respiratory metabolism was investigated through Seahorse Agilent assays, while oxidative stress level was assessed through fluorescent probes; DNA damage was evaluated by Comet assay, and mitochondrial morphology was analyzed in confocal microscopy. RESULTS: Results show that the initial response to CdCl2 involves mitochondria rearrangement into a perinuclear network. However, SOD1 and SOD2 activities are inhibited, leading to increased superoxide anion level, which in turn causes DNA strand breaks. From the metabolic point of view, cells increase their glycolytic flux, while all extra NADH produced is still efficiently reoxidized by mitochondria. CONCLUSIONS: Our results confirm previously shown response against cadmium toxicity; new data about glycolytic increase and mitochondrial rearrangements suggest pathways leading to cell transformation. GENERAL SIGNIFICANCE: In this work we exploit the widely used, well known CTA, which allows following healthy cells transformation into a malignant phenotype, to understand early events in cadmium-induced carcinogenesis.

Neuronal specific and non-specific responses to cadmium possibly involved in neurodegeneration: A toxicogenomics study in a human neuronal cell model.

Epidemiological data have linked cadmium exposure to neurotoxicity and to neurodegenerative diseases (e.g., Alzheimer's and Parkinson's disease), and to increased risk of developing ALS. Even though the brain is not a primary target organ, this metal can bypass the blood brain barrier, thus exerting its toxic effects. The coordination chemistry of cadmium is of strong biological relevance, as it resembles to zinc(II) and calcium(II), two ions crucial for neuronal signaling. A toxicogenomics approach applied to a neuronal human model (SH-SY5Y cells) exposed to cadmium (10 and 20 µM) allowed the identification of early deregulated genes and altered processes, and the discrimination between neuronal-specific and unspecific responses as possible triggers of neurodegeneration. Cadmium confirmed its recognized carcinogenicity even on neuronal cells by activating the p53 signaling pathway and genes involved in tumor initiation and cancer cell proliferation, and by down-regulating genes coding for tumor suppressors and for DNA repair enzymes. Two cadmium-induced stress responses were observed: the activation of different members of the heat shock family, as a mechanism to restore protein folding in response to proteotoxicity, and the activation of metallothioneins (MTs), involved in zinc and copper homeostasis, protection against metal toxicity and oxidative damage. Perturbed function of essential metals is suggested by the mineral absorption pathway, with MTs, HMOX1, ZnT-1, and Ferritin genes highly up-regulated. Cadmium interferes also with Ca2+ regulation as S100A2 is one of the top up-regulated genes, coding for a highly specialized family of regulatory Ca2+-binding proteins. Other neuronal-related functions altered in SH-SY5Y cells by cadmium are microtubules dynamics, microtubules motor-based proteins and neuroprotection by down-regulation of NEK3, KIF15, and GREM2 genes, respectively.

Cellulose nanocrystals are effective in inhibiting host cell bacterial adhesion.

The use of cellulose nanocrystals (CNCs) as a biomaterial able to inhibit host cell bacterial adhesion is described. Pre-incubation of E. coli ATCC 25922 with a suspension of 0.1% CNCs afforded a significant 2 log reduction of bacterial adhesion to the intestinal cell monolayer HT29. This effect could be attributed to the interaction between the CNCs and the bacterial cell surface as confirmed using fluorescence microscopy experiments.

Cadmium-transformed cells in the in vitro cell transformation assay reveal different proliferative behaviours and activated pathways.

The in vitro Cell Transformation Assay (CTA) is a powerful tool for mechanistic studies of carcinogenesis. The endpoint is the classification of transformed colonies (foci) by means of standard morphological features. To increase throughput and reliability of CTAs, one of the suggested follow-up activities is to exploit the comprehension of the mechanisms underlying cell transformation. To this end, we have performed CTAs testing CdCl2, a widespread environmental contaminant classified as a human carcinogen with the underlying mechanisms of action not completely understood. We have isolated and re-seeded the cells at the end (6weeks) of in vitro CTAs to further identify the biochemical pathways underlying the transformed phenotype of foci. Morphological evaluations and proliferative assays confirmed the loss of contact-inhibition and the higher proliferative rate of transformed clones. The biochemical analysis of EGFR pathway revealed that, despite the same initial carcinogenic stimulus (1µM CdCl2 for 24h), transformed clones are characterized by the activation of two different molecular pathways: proliferation (Erk activation) or survival (Akt activation). Our preliminary results on molecular characterization of cell clones from different foci could be exploited for CTAs improvement, supporting the comprehension of the in vivo process and complementing the morphological evaluation of foci.

Synthetic deoxynojirimycin derivatives bearing a thiolated, fluorinated or unsaturated N-alkyl chain: identification of potent α-glucosidase and trehalase inhibitors as well as F508del-CFTR correctors.

The synthesis of eleven 1-deoxynojirimycin (DNJ) derivatives presenting either a monofluoro, difluoro, thiolated or unsaturated N-alkyl chain of various length is described. Exploiting the unsaturated moiety on the nitrogen, fluorine has been introduced through a HF/SbF5 superacid catalysed hydrofluorination and thiol-ene click chemistry allowed introduction of sulfur. The synthetic derivatives have been tested for their ability to inhibit glycosidases and correct F508del-CFTR. Two of the unsaturated iminosugars exhibited potency similar to Miglustat as F508del-CFTR correctors. The thioalkyl iminosugars as well as the corresponding alkyl iminosugars demonstrated low micromolar α-glucosidases and trehalases inhibition. Introduction of fluorine abolished F508del-CFTR correction and trehalase inhibition.

Role of water in chromosome spreading and swelling induced by acetic acid treatment: a FTIR spectroscopy study.

The so called chromosome preparation is a procedure consisting of three strictly connected stages that enables to obtain chromosomes of quality suitable for cytogenetic analysis. Interestingly, experimental evidence strongly suggested that chromosome spreading and swelling (key processes that allow their counting and detailed structural analysis) are induced in the last fixative-evaporation stage by the interaction, mediated by acetic acid, between water from the environmental humidity, and the cytoplasmic matrix and the chromatin. However, since a considerable variation in the quality of chromosome preparations is observed, strongly depending on the environmental conditions in which the procedure takes place, a better comprehension of the mechanisms underlying chromosome preparation is required. To this aim, here we analysed intact lymphocytes before and at each stage of the chromosome preparation protocol by Fourier transform infrared (FTIR) spectroscopy, a technique widely used for the study not only of isolated biomolecules, but also of complex biological systems, such as whole cells. Interestingly, we found that the chromosome preparation protocol induces significant structural changes of cell proteins and DNA, in particular due to the interaction with acetic acid. Moreover, noteworthy, through the monitoring of changes in the water combination band between 2300 and 1800 cm-1, we provided evidence at molecular level of the crucial role of the bound water to the cytoplasmic matrix and to the chromatin in determining the chromosome spreading and swelling. Our FTIR results, therefore, underline the need to perform the last fixative-evaporation stage in standardized and optimized temperature and relative humidity conditions, thus providing chromosomes of high quality for the cytogenetic analysis that would lead in this way to more reliable results.

[Nocturnal hemodialysis: an alternative treatment for a better quality of life]. / Emodialisi notturna: un trattamento alternativo per una migliore qualità della vita.

The interest of investigators in intensified dialysis regimens has been growing in recent years, especially since the HEMO Study Group showed that a higher dose of thrice-weekly hemodialysis fails to reduce mortality and morbidity but improves clinical outcomes. Alternative hemodialysis strategies including short daily hemodialysis (SDHD), long hemodialysis (LHD) and nocturnal daily hemodialysis (NDHD) have been developed in the hope to improve patients' outcomes. A growing number of investigators are studying patients on alternative dialysis regimens and most publications in this field have reported significant improvements in clinical outcomes including left ventricular hypertrophy, blood pressure control, anemia, calcium-phosphate metabolism, and fluid and electrolyte balance; all of these parameters can be considered as indirect signs of improvement in quality of life. However, the strength of these results is often limited by shortcomings in study design. Indeed, in most of these studies an adequate control group is missing, the patient groups are not properly matched, and the number of patients enrolled is small. Similarly, most studies have evaluated the effects of NDHD and/or nocturnal LHD on health-related quality of life (HRQoL) by questionnaire administration. Even though better results might be achieved with nocturnal hemodialysis, no conclusive data exist to prove statistically significant differences in HRQoL between conventional and intensive hemodialysis. In conclusion, all of these novel dialysis strategies offer reliable opportunities for uremic patients, but further trials are needed to determine whether alternative hemodialysis can reduce morbidity and mortality in this high-risk population of patients.

Gamma glutamyltranspeptidase activity and viral hepatitis in dialysis population.

BACKGROUND: Numerous investigations have reported that viral hepatitis is associated with significant hepatocellular damage, as expressed by raised aminotransferases in serum, in dialysis population. However, scarce information exists on the activity of gamma glutamyltranspeptidase (GGTP) in dialysis patients with infection by hepatotropic viruses. OBJECTIVES: We measured serum GGTP values in a large cohort (n=757) of patients receiving long-term dialysis; healthy controls were also included. The relationship between GGTP values and a series of demographic, clinical, and biochemical parameters was analyzed. METHODS: Serum GGTP levels were tested by spectrophotometry. A subset (n=333) of dialysis patients was tested by molecular technology (branched-chain DNA (bDNA) assay) to evaluate the relationship between serum GGTP and HCV viremia. A subgroup (n=78) of dialysis patients was analyzed by an ultrasound scan of gallbladder and biliary tract to assess the presence of gallstone disease. Multivariate analyses were made using regression models; serum GGTP values were included as a dependent variable. The usefulness of serum GGTP levels in detecting HBsAg and anti-HCV positivity was evaluated using receiver operating characteristics (ROC) curve analysis. RESULTS: Univariate analysis showed that serum GGTP levels were significantly higher in HBsAg positive and/or anti-HCV positive patients than in HBsAg negative/anti-HCV negative patients on dialysis; 85.1+/-184.1 versus 25.86+/-23.9 IU/l (P=0.0001). The frequency of raised GGTP levels was 22.2% (41/184) among dialysis patients with chronic viral hepatitis. Multivariate analysis showed a significant and independent association between serum GGTP values and positive HBsAg (P=0.005) and anti-HCV antibody (P=0.0001) status. Mean GGTP values were significantly higher in study patients than controls, 32.32+/-60.02 versus 23.5+/-16.92 IU/L (P=0.01); however, no significant difference with regard to GGTP between study and healthy cohorts persisted after correction for age, gender, race, and viral markers. No relationship between gallstone disease and serum GGTP was found (NS). An independent and significant association (P=0.0291) between raised GGTP levels and detectable HCV RNA in serum was noted among patients tested by biology molecular techniques. ROC technology demonstrated that GGTP was equally useful for detecting HBV (P=0.0004) and HCV (P=0.0005) among dialysis patients. CONCLUSIONS: We found an independent and significant association between serum GGTP values and HBsAg and/or anti-HCV antibody in dialysis population. Twenty-two percent of dialysis patients with chronic viral hepatitis had elevated GGTP. No difference in GGTP between HBsAg- negative/anti-HCV- negative dialysis patients and healthy individuals was found. Routine testing for serum GGTP levels to assess liver disease induced by hepatotropic viruses or other agents in dialysis population is suggested.

Leucine methyl ester is a powerful allosteric activator of the neutral amino acid cotransport system in Bombyx mori larval midgut.

We have identified three methyl esters that have a potent stimulatory effect on the cotransport system responsible for the absorption of most essential amino acids in the silkworm Bombyx mori. L-Leucine methyl ester, the most powerful activator, determined a large dose-dependent, K(+)-independent increase of leucine uptake into midgut brush border membrane vesicles. Kinetic experiments revealed non-essential mixed-type activation, with K(a) values of 27+/-2 and 47+/-8 microM in the presence and in the absence of K(+), respectively. The activation increased K(m) twofold, and V(max) up to 18-fold depending upon the experimental conditions. Leucine uptake mediated by the amino acid uniport appears to be unaffected by the activator.

Leucine transport in membrane vesicles from Chironomus riparius larvae displays a mélange of crown-group features.

Leucine uptake into membrane vesicles from larvae of the midge Chironomus riparius was studied. The membrane preparation was highly enriched in typical brush border membrane enzymes and depleted of other membrane contaminants. In the absence of cations, there was a stereospecific uptake of l-leucine, which exhibited saturation kinetics. Parameters were determined both at neutral (Km 33 +/- 5 microM and Vmax 22.6 +/- 6.8 pmol/7s/mg protein) and alkaline (Km 46 +/- 5 microM and Vmax 15.5 +/- 2.5 pmol/7s/mg protein) pH values. At alkaline pH, external sodium increased the affinity for leucine (Km 17 +/- 1 microM) and the maximal uptake rate (Vmax 74.0 +/- 12.5 pmol/7s/mg protein). Stimulation of leucine uptake by external alkaline pH agreed with lumen pH measurements in vivo. Competition experiments indicated that at alkaline pH, the transport system readily accepts most L-amino acids, including branched, unbranched, and alpha-methylated amino acids, histidine and lysine, but has a low affinity for phenylalanine, beta-amino acids, and N-methylated amino acids. At neutral pH, the transport has a decreased affinity for lysine, glycine, and alpha-methylleucine. Taken together, these data are consistent with the presence in midges of two distinct leucine transport systems, which combine characters of the lepidopteran amino acid transport system and of the sodium-dependent system from lower neopterans.

Polymorphism of the angiotensin-converting enzyme gene in end-stage renal failure patients.

The plasma levels of angiotensin-converting enzyme (ACE) are modulated by the insertion (I)/deletion (D) polymorphism within the ACE gene locus. An association between progressive renal disease, raised cardiovascular risk, and ACE plasma levels has been shown. To evaluate the genotype frequencies of the I/D polymorphism in terminal renal failure, we have enrolled 341 dialysis patients (321 on hemodialysis and 20 on peritoneal dialysis) in a district of southern Italy (Foggia). As controls, 1,307 subjects from the same area have been enrolled. Genomic DNA was obtained from leukocytes, and the ACE I/D polymorphism was determined by polymerase chain reaction. Among uremics, 151 subjects (44.3%) carried the DD genotype, 149 (43.7%) the ID, and 41 (12.0%) the II genotype. In controls, 560 subjects (42.8%) had the DD genotype, 577 (44.1%) the ID, and 170 (13.1%) the II genotype (p = n.s.). Among patients, the frequency of DD subjects was higher in men (48.3%) than in women (39. 7%, p < 0.01). A slight different frequency of the DD genotype was found according to the duration of dialysis treatment: 47.5% in patients on dialysis up to 60 months and 41.7 and 40.6% in those with a dialytic age of 60-120 and >120 months, respectively (p for trend: 0.53). Patients with or without cardiovascular diseases, such as hypertension, left ventricular hypertrophy, coronary artery disease, and chronic cardiac failure, did not exhibit any difference in ACE I/D allele and genotype frequencies (p always >0.05). In conclusion, frequencies of the ACE DD genotype were similar in uremics and in controls and did not differ between patients with and without cardiovascular diseases. A nonsignificant inverse relationship with the time spent on dialysis was observed, suggesting that ACE I/D polymorphism may influence the cardiovascular death rate.

Substrate specificity of the brush border K+-leucine symport of Bombyx mori larval midgut.

L-leucine uptake into membrane vesicles from Bombyx mori larval midgut was tested for inhibition by 55 compounds, which included sugars, N-methylated, alpha-, beta-, gamma-, delta-, epsilon-amino acids, primary amines, alpha-amino alcohols, monocarboxylic organic acids and alpha-ketoacids. Based on cis-inhibition experiments performed at the high pH (10.8) characteristic of the midgut luminal content in vivo, we find that the carrier binding site interacts with molecules which possess a well-defined set of structural features. Amino acids are preferentially accepted as anions and the ideal inhibitor must have an hydrophobic region and a polar head constituted by a chiral carbon atom bearing two hydrophilic groups, a deprotonated amino-group and a dissociated carboxylic group. Binding is reduced if one of the two hydrophilic groups is removed. Lowering the pH to less alkaline value (8.8) only affects the affinity of delta- and epsilon-amino acids, which are excluded from binding because of their positively charged side-chain. Modifications of the potassium electrochemical gradient increased the affinity constant values of the molecules, but have little effect on the rank of specificity. Physiological implications of the data reported are discussed.

Hepatitis C virus infection in four haemodialysis units of southern Italy: epidemiological report.

UNLABELLED: The haemodialysis patients are an high risk population for hepatitis viral infections. While the incidence of HBV has decreased worldwide, HCV is now the major cause of viral infection in these patients. The aim of our study was to define a complete map of patients undergoing routine replacement therapy by haemodialysis in the province of Foggia, Southern Italy, who were HCV Ab positive, the presence of viraemia and their genotypes; moreover, we investigated the probable factors involved in determining the infection as well as the means of prevention. MATERIALS AND METHODS: We enrolled 330 patients treated in four haemodialysis centres (DC) and six secondary units; mean age was 57 years and mean duration of dialysis 76 months. Samples were drawn to determine cytolysis indexes and the HCV Ab status; in HCV positive patients, we also looked for viraemia and HCV genotypes. Data were analysed by a transversal cross-section study. RESULTS AND CONCLUSIONS: Prevalence of HCV infection was 0.43 (males 0.45, females 0.42). The risk of contracting the infection was shown to be significantly different in the various DCs and did not seem to be related to the severity of the preventive measures. There was no significant difference between the various DCs in the comparison between the odds of HCV-RNA+ and HCV-RNA- patients. No significant prevalence of a given genotype emerged from a cross-sectional study related to the comparison between different genotypes. Moreover, transfusions of blood products seemed to have no significant relation to HCV infection. Finally, patients treated with haemodialysis for more than 36 months run a seven time greater risk of contracting HCV infection.

Effect of coexistent diseases on survival of patients undergoing dialysis.

A cohort retrospective study was used to analyze the effect of comorbidity on survival of end-stage renal disease (ESRD) patients undergoing dialysis. The authors analyzed the survival of 255 patients (144 men, 111 women; median age 54 years; range 8-81 years) followed at the District Hemodialysis Unit in Foggia, Italy, over a 15 year period (median follow-up 30 months; range 1-190 months). Two subscales assessing the overall severity of the identified coexistent diseases and overall physical impairment, and a composite four level index of coexistent diseases (ICED) were assembled using information recorded at the time of admission. The Cox proportional hazard model was applied to evaluate the association of various patient characteristics with the probability of death. Mortality risk was associated with patient age (RR = 3.4 for patients aged 42-61; RR = 4.8 for patients older than age 61 compared with patients younger than age 42), initial condition leading to renal failure (RR = 3.1 for diabetes compared with primary renal disease) and ICED (RR = 3.0 for patients with uncontrolled coexistent disease or severe impairment compared with patients with no coexistent disease and no or mild impairment). Gender and type of dialysis were not associated with mortality risk. It was concluded that, as is the case with other chronic conditions, co-morbidity is a powerful independent prognostic factor in determining the mortality of ESRD patients.

HCV infections in dialysis patients.

HCV is seen as an emergent problem in Dialysis Units; in fact, the patients of these centers are at high risk for blood-transmitted infections, through coming microepidemies. For this reason and using the same method, we have studied the prevalence of anti-HCV and virus-derived hepatitis in a dialytic population of 105 patients. The prevalence of anti-HCV was 25.71%.