ALBERT

Description: This study explores the role of model resolution on the simulation of precipitation and on the estimate of its future change in the Mediterranean region. It compares the results of two regional climate models (RCMs, with two different horizontal grid resolutions, 0.44 and 0.11 degs, covering the whole Mediterranean region) and of the global climate model (GCM, 0.75 degs) that has provided the boundary conditions for them. The regional climate models include an interactive oceanic component with a resolution of 1/16 degs. The period 1960–2100 and the representative concentration pathways RCP4.5 and RCP8.5 are considered. The results show that, in the present climate, increasing resolution increases total precipitation and its extremes over steep orography, while it has the opposite effect over flat areas and the sea. Considering climate change, in all simulations, total precipitation will decrease over most of the considered domain except at the northern boundary, where it will increase. Extreme precipitation will increase over most of the northern Mediterranean region and decrease over the sea and some southern areas. Further, the overall probability of precipitation (frequency of wet days) significantly decreases over most of the region, but wet days will be characterized with precipitation intensity higher than the present. Our analysis shows that: (1) these projected changes are robust with respect to the considered range of model resolution; (2) increasing the resolution (within the considered resolution range) decreases the magnitude of these climate change effects. However, it is likely that resolution plays a less important role than other factors, such as the different physics of regional and global climate models. It remains to be investigated whether further increasing the resolution (and reaching the scale explicitly permitting convection) would change this conclusion.

Description: The ingestion of gluten has been associated with gastrointestinal symptoms even in the absence of detectable immune responses. Little is known about the pathophysiological effects of gluten on the upper gastrointestinal tract. We aimed to assess whether the ingestion of gluten leads to an impairment of the physiological mechanisms of gastric emptying, gallbladder contraction and relaxation. A total of 17 healthy subjects underwent ultrasound evaluation of gastric emptying dynamics and gallbladder contractions at baseline and every 30 min after a standard gluten-containing and gluten-free meal (250 kcal, 70% carbohydrates). The pattern of gastric emptying was similar after a standard meal with or without gluten, but differed in terms of the peak of the antral filling curve, which was wider (mean area 5.69, median 4.70, range 3.71‒9.27 cm2 vs. mean 4.89, median 4.57, 2.27‒10.22 cm2, p = 0.023) after the gluten-containing meal. The pattern of gallbladder contractions was different after the gluten-free meal (p 〈 0.05), with higher gallbladder volumes in the late refilling phases. The results of this study show that gluten ingestion exerts objective effects on gastric and gallbladder motility. Although the underlying pathophysiological mechanism remains unknown, these results could account for some of the gluten-related symptoms reported by patients with celiac disease and non-celiac gluten sensitivity.

Description: Background and aim. Transient elastography (TE) is a new, non-invasive and reproducible technique that measures liver stiffness (LSM). It has been demonstrated to be a reliable tool for assessing hepatic fibrosis and cirrhosis in patients with chronic liver disease (CLD). However, its role in patients with b- thalassemia has not been extensively investigated. The aim of the present study was to assess LSM and its possible correlation with iron overload in HCV positive patients with b- thalassemia major and intermedia. Methods. During a six-month period (from January to June 2007) 46 consecutive adults patients with b- thalassemia afferring to a single Italian Thalassemia Care Center in Milan, Italy, were enrolled in the study. Twenty-nine patients (Group I: 7 M and 23 F; mean age 31±SD 7.1 yrs; mean BMI 23.4±SD 3 Kg/m2) had b- thalassemia major and 17 intermedia (Group II: 10 M and 7 F; mean age 43±SD12.4 yrs; BMI 22 ±SD 3 Kg/m2). Sixteen patients (55%) in group I and two (12%) in group II were HCV RNA positive. All patients were examined by TE (FibroScan®; Echosens, Paris, France) and only the examinations with at least 10 validated measurements and a success rate of at least 60% were considered adequate. According to a previous study in CLD patients the considered TE cut off to diagnosing different stages of hepatic fibrosis were: 〉7.9 kPa for F≥2; 〉10.3 for ≥F3 and 〉11.9 for F=4. Twelve patients (all in group I) also had undergone liver biopsy. Necroinflammation and fibrosis were scored by METAVIR classification; liver iron concentration (LIC, mg/gr of liver dry weight) was measured on fresh tissue cores by atomic absorption spectrometry. Twenty-five patients underwent liver iron determination by T2* Magnetic Resonance Imaging (MRI) assessment. Results. In patients who underwent liver biopsy, LSM increased proportionally to the METAVIR stage and a significant positive correlation was observed between LSM and fibrosis stage (r=0.57, p= 0.039). Patients in group I had significantly higher values of mean LSM values (10.6± SD 9.3 kPa) and serum ferritin (SF) (1367±SD 1169 ng/mL) than those in group II (6.0± SD 3.3 kPa and 716±SD 472 ng/mL, respectively) (p=2) or severe fibrosis (F〉=3) did not differ significantly according to HCV viremic status. Conclusion TE is a reliable non invasive technique to stage liver fibrosis in patients with b- thalassemia major. In these patients with concomitant HCV infection a significant or severe fibrosis was observed in about one third of the cases. Apart from fibrosis also serum necroinflammatory activity, GGT levels and SF levels may influence LSM values. The reliability of liver iron overload by T2* MRI evaluation remains still to be validated.

Description: Abstract 2003 Poster Board I-1025 Background & Aims Clinical presentation of hereditary hemochromatosis markedly changed in the recent years. The aim of the study was to analyze a large series of consecutive Italian patients with hemochromatosis diagnosed between 1976 and 2007 to define whether the genetic background and the presence of acquired risk factors influenced the severity of iron overload and the natural history of the disease across the years. Methods: A cohort of 452 Italian patients with iron overload, of whom 338 HFE-related (C282Y homozygotes or compound C82Y/H63D heterozygotes, and 114 non-HFE-related, prospectively followed for a median of 112 months. Results: Alcohol intake, smoking habits and iron removed to depletion were similar in patients with and without HFE-related iron overload. HBV (4% and 10% p=0.03) and HCV (9% and 17% p=0.02) infections were more frequent in patients with non-HFE-related iron overload. Seventy-three percent and 61% of the patients with HFE and non-HFE-related disease had no acquired risk factor. Cirrhosis was significantly more frequent in non-HFE patients, independently of the presence of acquired risk factors (p=0.02). Gender, alcohol intake, prevalence of smokers, HCV infection, glucose, lipids, iron-related parameters and prevalence of C282Y/H63D significantly differed across the years. At enrolment cirrhosis was present in 145 cases, being significantly more frequent in the first decade (80%, 47% and 13%, p=0.001). Survival did not differ across the decades in cirrhotic patients, HCC occurring similarly in HFE and non-HFE patients. Conclusion: Patients with HFE and non-HFE related iron overload have comparable iron overload and similar clinical history. Patients, unless cirrhotics at enrolment, diagnosed during the last 10 years have less severe disease and lower prevalence of acquired risk factors, independently of genetic background. Disclosures: No relevant conflicts of interest to declare.

Description: In genetic hemochromatosis (GH), iron overload affects mainly parenchymal cells, whereas little iron is found in reticuloendothelial (RE) cells. We previously found that RE cells from GH patients had an inappropriately high activity of iron regulatory protein (IRP), the key regulator of intracellular iron homeostasis. Elevated IRP should reflect a reduction of the iron pool, possibly because of a failure to retain iron. A defect in iron handling by RE cells that results in a lack of feedback regulation of intestinal absorption might be the basic abnormality in GH. To further investigate the capacity of iron retention in RE cells of GH patients, we used inflammation as a model system as it is characterized by a block of iron release from macrophages. We analyzed the iron status of RE cells by assaying IRP activity and ferritin content after 4, 8, and 24 hours of incubation with lipopolysaccharide (LPS) and interferon-γ (IFN-γ). RNA-bandshift assays showed that in monocytes and macrophages from 16 control subjects, IRP activity was transiently elevated 4 hours after treatment with LPS and IFN-γ but remarkably downregulated thereafter. Treatment with NO donors produced the same effects whereas an inducible Nitric Oxide Synthase (iNOS) inhibitor prevented them, which suggests that the NO pathway was involved. Decreased IRP activity was also found in monocytes from eight patients with inflammation. Interestingly, no late decrease of IRP activity was detected in cytokine-treated RE cells from 12 GH patients. Ferritin content was increased 24 hours after treatment in monocytes from normal subjects but not in monocytes from GH patients. The lack of downregulation of IRP activity under inflammatory conditions seems to confirm that the control of iron release from RE cells is defective in GH.

Description: Before the introduction of hepatitis C virus (HCV) screening for blood donors, the risk of acquiring HCV infection as a result of a transfusion was about 10%. The aim of this study was to assess the frequency and rate of progression to cirrhosis in patients with transfusion-associated chronic HCV infection and identify possibly negative prognostic factors. Of 2477 consecutive patients with clinical or laboratory evidence of liver disease, 392 (16%) were anti-HCV– and HCV-RNA–positive, had anamnestic evidence of a single and precisely dated transfusion event, and showed no other causes of chronic liver disease; 268 (68%) underwent ultrasound-guided liver biopsy and were enrolled in the study. After a mean interval of 18.4 years, 54 patients (20.1%) had cirrhosis, which multivariate analysis showed to be independently associated with the duration of follow-up, age at infection and at the time of liver biopsy, and serum alanine aminotransferase levels at biopsy. The time necessary to have a 50% probability of developing cirrhosis in patients aged 21-30, 31-40, and more than 40 years was 33, 23, and 16 years, respectively. In comparison with those aged 20 years or less at infection, the risk ratio of developing cirrhosis over a period of 30 years for patients aged 21-30 and at least 31 years at infection was, respectively, 4.51 (95% confidence interval, 1.03-19.76) and 12.29 (95% confidence interval, 3.06-49.40). In patients with transfusion-associated chronic hepatitis C, the risk of cirrhosis is related to age at infection and disease activity. Our findings suggest that an aggressive therapeutic approach should be adopted in patients infected by HCV at an older age to prevent the progression to end-stage liver disease.

Description: Cytokine-treated macrophages represent a useful model to unravel the molecular basis of reticuloendothelial (RE) iron retention in inflammatory conditions. In the present study, we showed that stimulation of murine macrophage J774 cells with interferon (IFN)-γ/lipopolysaccharide (LPS) resulted in a nitric oxide-dependent modulation of the activity of iron regulatory proteins (IRP)-1 and 2, cytoplasmic proteins which, binding to RNA motifs called iron responsive elements (IRE), control ferritin translation. Stimulation with cytokines caused a small increase of IRP-1 activity and a strong reduction of IRP-2 activity accompanied by increased ferritin synthesis and accumulation. Cytokines induced only a minor increase of H chain ferritin mRNA, thus indicating that IRP-2–mediated posttranscriptional regulation plays a major role in the control of ferritin expression. This was confirmed by direct demonstration that the translational repression function of IRP was impaired in stimulated cells. In fact, translation in cell-free extracts of a reporter transcript under the control of an IRE sequence was repressed less efficiently by IRP-containing lysates from cytokine-treated cells than by lysates from control cells. Our findings throw light on the role of IRP-2 showing that: (1) this protein responds to a stimulus in opposite fashion to IRP-1; (2) when abundantly expressed, as in J774 cells, IRP-2 is sufficient to regulate intracellular iron metabolism in living cells; and (3) by allowing increased ferritin synthesis, IRP-2 may play a role in the regulation of iron homeostasis in RE cells during inflammation.

Description: Cytokine-treated macrophages represent a useful model to unravel the molecular basis of reticuloendothelial (RE) iron retention in inflammatory conditions. In the present study, we showed that stimulation of murine macrophage J774 cells with interferon (IFN)-γ/lipopolysaccharide (LPS) resulted in a nitric oxide-dependent modulation of the activity of iron regulatory proteins (IRP)-1 and 2, cytoplasmic proteins which, binding to RNA motifs called iron responsive elements (IRE), control ferritin translation. Stimulation with cytokines caused a small increase of IRP-1 activity and a strong reduction of IRP-2 activity accompanied by increased ferritin synthesis and accumulation. Cytokines induced only a minor increase of H chain ferritin mRNA, thus indicating that IRP-2–mediated posttranscriptional regulation plays a major role in the control of ferritin expression. This was confirmed by direct demonstration that the translational repression function of IRP was impaired in stimulated cells. In fact, translation in cell-free extracts of a reporter transcript under the control of an IRE sequence was repressed less efficiently by IRP-containing lysates from cytokine-treated cells than by lysates from control cells. Our findings throw light on the role of IRP-2 showing that: (1) this protein responds to a stimulus in opposite fashion to IRP-1; (2) when abundantly expressed, as in J774 cells, IRP-2 is sufficient to regulate intracellular iron metabolism in living cells; and (3) by allowing increased ferritin synthesis, IRP-2 may play a role in the regulation of iron homeostasis in RE cells during inflammation.

Description: In genetic hemochromatosis (GH), excess iron is deposited in parenchymal cells, whereas little iron is found in reticuloendothelial (RE) cells until the later stages of the disease. As iron absorption is inversely related to RE cells stores, a failure of RE to retain iron has been proposed as the basic defect in GH. In RE cells of GH subjects, we examined the activity of iron regulatory protein (IRP), a reliable indicator of the elusive regulatory labile iron pool, which modulates cellular iron homeostasis through control of ferritin (Ft) and transferrin receptor gene expression. RNA-bandshift assays showed a significant increase in IRP activity in monocytes from 16 patients with untreated GH compared with 28 control subjects (1.5-fold) and five patients with secondary hemochromatosis (SH) with similar iron burden (fourfold). In 17 phlebotomy-treated GH patients, IRP activity did not differ from that of control subjects. In both GH and SH monocyte-macrophages, Ft content increased by twofold and the L subunit-rich isoferritin profile was unchanged as compared with controls. IRP activity was still upregulated in vitro in monocyte-derived macrophages of GH subjects but, following manipulations of iron levels, was modulated normally. Therefore, the sustained activity of monocyte IRP found in vivo in monocytes of GH patients is not due to an inherent defect of its control, but is rather the expression of a critical abnormality of iron metabolism, eg, a paradoxical contraction of the regulatory iron pool. By preventing Ft mRNA translation, high IRP activity in monocytes may represent a molecular mechanism contributing to the inadequate Ft accumulation and insufficient RE iron storage in GH.