Maria Teresa Vilei

Liver repopulation with bone marrow-derived cells improves the metabolic disorder in the Gunn rat

Background: Reversible ischaemia/reperfusion (I/R) liver injury has been used to induce engraftment and hepatic parenchymal differentiation of exogenous β2-microglubulin−/Thy1+ bone marrow derived cells. Aim: To test the ability of this method of hepatic parenchymal repopulation, theoretically applicable to clinical practice, to correct the metabolic disorder in a rat model of congenital hyperbilirubinaemia. Methods and results: Analysis by confocal laser microscopy of fluorescence labelled cells and by immunohistochemistry for β2-microglubulin, 72 hours after intraportal delivery, showed engraftment of infused cells in liver parenchyma of rats with I/R, but not in control animals with non-injured liver. Transplantation of bone marrow derived cells obtained from GFP-transgenic rats into Lewis rats resulted in the presence of up to 20% of GFP positive hepatocytes in I/R liver lobes after one month. The repopulation rate was proportional to the number of transplanted cells. Infusion of GFP negative bone marrow derived cells into GFP positive transgenic rats resulted in the appearance of GFP negative hepatocytes, suggesting that the main mechanism underlying parenchymal repopulation was differentiation rather than cell fusion. Transplantation of wild type bone marrow derived cells into hyperbilirubinaemic Gunn rats with deficient bilirubin conjugation after I/R damage resulted in 30% decrease in serum bilirubin, the appearance of bilirubin conjugates in bile, and the expression of normal UDP-glucuronyltransferase enzyme evaluated by polymerase chain reaction. Conclusions: I/R injury induced hepatic parenchymal engraftment and differentiation into hepatocyte-like cells of bone marrow derived cells. Transplantation of bone marrow derived cells from non-affected animals resulted in the partial correction of hyperbilirubinaemia in the Gunn rat.

Conjugated bilirubin in neonates with glucose-6-phosphate dehydrogenase deficiency

We used a system capable of measuring conjugated bilirubin and its monoconjugated and diconjugated fractions in serum to assess bilirubin conjugation in 29 glucose-6-phosphate dehydrogenase (G6PD)-deficient, term, male newborn infants and 35 control subjects; all had serum bilirubin levels > or = 256 mumol/L (15 mg/dI). The median value for diconjugated bilirubin was lower in the G6PD-deficient neonates than in control subjects (0.06 (range 0.00 to 1.84) vs 0.21 (range 0.00 to 1.02) mumol/L, p = 0.006). Diglucuronide was undetectable in 11 (38.9%) of the G6PD-deficient infants versus 3 (8.6%) of the control subjects (p = 0.015). These findings imply a partial defect of bilirubin conjugation not previously demonstrated in G6PD-deficient newborn infants.

Intraportal hepatocyte transplantation in the pig: a hemodynamic and histopathological study1

Background. Hepatocyte transplantation is an attractive treatment for various liver diseases. The intraportal route of transplantation is favored, but little information is available on the possible adverse effects in this technique. We investigated the influence of intraportal loads of hepatocytes on portal, pulmonary, and systemic hemodynamics in 13 pigs. Methods. Under general anesthesia, pigs were provided with an arterial line, a Swan-Ganz catheter, and two intraportal catheters, one for cell infusion and one for heparin infusion and portal pressure measurement. Pig hepatocytes were infused at a rate of 25 million cells/min. Results. The first six animals were used to develop the infusion technique. In the last seven animals, portal pressure increased linearly with cell load upon infusion of 400–2400×106 hepatocytes (r2=0.704;P <0.05). Portal flow measured by Doppler sonography decreased by 23–66% below basal values. An inverse linear relationship was found between portal pressure and portal flow (r2=0.679;P <0.05), portal flow approaching zero for portal pressure >40 mmHg. Pulmonary arterial pressure increased by 11–62%. AST increased up to 10-fold, and platelets decreased by 22–58%. Hepatocytes-containing thrombi were present in segmental and in smaller portal branches. Hepatocytes were always identified in lung sinusoids 48 hr after infusion, and a small basal pulmonary infarction was found in one animal. Conclusions. These data suggest that up to 2.4% of total hepatocyte mass can be infused in this large animal model. However, the risk of significant thrombotic complications should be considered for clinical applications.

Unconjugated and Conjugated Bilirubin Pigments during Perinatal Development

Objective: To determine the effect of phototherapy on serum conjugated bilirubin fractions, an index of bilirubin conjugation, in hyperbilirubinemic neonates. Method: Serum was sampled from 21 jaundiced (serum diazo total bilirubin ≥274 µmol/l), term, otherwise healthy neonates prior to starting phototherapy, and 24 h after the commencement of treatment. Alkaline methanolysis followed by reverse-phase, high-performance liquid chromatography, specific for determination of unconjugated bilirubin and the monoconjugated and diconjugated fractions of total conjugated bilirubin in serum, was used for the analysis. Prephototherapy values were compared to those at 24 h. Results: Serum total bilirubin and total conjugated bilirubin values decreased during the study period, from 220 (211–239) to 177 (157–213) µmol/l (median (25–75% range)) p = 0.001, for the former, and from 1.4 (0.87–1.57) to 0.93 (0.69–1.84) µmol/l, p = 0.005, for the latter. These parameters decreased by a similar percentage (–16.6 ± 14.8% and –14.0 ± 23.4%, respectively; p > 0.05). Both monoconjugated and diconjugated bilirubin, calculated as a percentage of total conjugated bilirubin, remained constant over the study period (88.2 (72.2–96.4)% before phototherapy and 92.5 (87.3–96.8)% after 24 h, p > 0.05, for monoconjugated bilirubin, and 11.8 (3.6–27.8)% and 7.5 (3.2–12.7)%, respectively, p > 0.05, for diconjugated bilirubin). Conclusions: Serum total conjugated bilirubin values decreased in parallel to serum total bilirubin levels during phototherapy, maintaining a constant relationship between these two parameters. The ratios of monoconjugated and diconjugated bilirubin to total conjugated bilirubin remained constant. These findings imply that phototherapy does not alter bilirubin conjugation in hyperbilirubinemic neonates.

Densitometric Threshold and Vertebral Fractures in Heart Transplant Patients

Background. Bone disease is one of the major complications of solid organ transplantation, causes considerable morbidity, and most patients are treated with immunosuppressant drugs after graft. The majority of studies reported rapid bone loss and an increased incidence of fractures after transplantation. The aim of our study was to evaluate osteoporosis and fracture prevalence, bone metabolism, and the effect of immunosuppressant agents on bone after heart transplantation. Methods. We planned a cross-sectional study in 180 heart transplant patients recruited from 3 different centers with a less than 10 years from graft. Each patient underwent a densitometric scan, and in 157 of them, an x-ray of the spine was performed to evaluate fractures. Biochemical assessment of bone metabolism was made at the time of the visit. Physical activity, diet, and calcium intake were evaluated using a specific questionnaire. Results. Vertebral fractures were diagnosed in 40% of subjects, but densitometric osteoporosis was observed only in 13% of spine and in 25% of hip scans. Interestingly, increasing T-score threshold up to −1.5 standard deviation, the prevalence of fractured patient improved significantly, reaching 60% in both genders. Bone content was inversely correlated with glucocorticoids, while a positive correlation was found with cyclosporine A. Almost all subjects had vitamin D deficiency. Conclusions. Standard densitometric criteria are unreliable to identify bone fragility after transplantation, and a different threshold (−1.5 standard deviation) should be considered. Transplanted patients should be adequately supplemented with vitamin D, and the effects of immunosuppressant agents on bone need further investigation.

Declining trends in the incidence of hip fractures in people aged 65 years or over in years 2000–2011

BACKGROUND The aim of this study was to explore hip fracture (HFx) incidence in the Veneto Region of Italy, looking at potential differences with the national data. METHODS We analyzed HFx incidence for people aged 65years or over, in years 2000-2011, using data from the Regional Hospitalization Database. Patients were stratified by sex, calendar year and 5-year age class. Data for the single provinces of the Region were also obtained. Absolute number of HFx, crude incidence for 10,000 inhabitants and age-standardized fracture rates were calculated. RESULTS During the study period, there were 53,917 hospitalizations for HFx (77.7% in females). In the whole 11year period of observation, the absolute HFx number increased by 17.7% in males and 10.6% females, respectively. However, age-standardized incidence rates declined by 18% in the same period (IRR 0.82, 95% CI 0.78-0.87). This decreasing trend was almost identical through all the age-cohorts up to 84years. In the whole study period, HFx incidence was lower for Padova (IRR 0.63, 95% CI 0.60-0.66) and Verona (IRR 0.66, 95% CI 0.63-0.70) provinces as compared to the others. This regional profile was quite different with respect to the data published, for the same calendar years, for Italy as a whole, in spite of an almost identical demography of the population. CONCLUSIONS HFx incidence is declining in the Veneto Region of Italy. Further studies, aimed to investigate factors involved in this figure are needed.

Unconjugated and conjugated bilirubin pigments during perinatal development: III. Studies on serum of breast-fed and formula-fed neonates

The process of conjugation and secretion of bilirubin was studied in a group of healthy, full-term, exclusively breast-fed newborns and a control group of exclusively formula-fed infants by means of a reverse-phase high-performance liquid chromatographic analysis of bilirubins present in serum. The serum concentrations of unconjugated bilirubin, esterified bilirubin, and the proportion of diesterified bilirubin (as percent of esterified bilirubin) were not significantly different in breast- and formula-fed infants on the 3rd and 5th days of life. These data suggest that both bilirubin production and conjugation are not different in breast-fed and in formula-fed newborns.

Effect of withdrawal of pravastatin on biliary lipid composition in humans.

Abrupt withdrawal of HMG-CoA reductase inhibitors is associated with increased excretion of cholesterol into bile, but this phenomenon has not been investigated in humans. In order to evaluate whether patients interrupting these hypolipidemic drugs are at increased risk of forming gallstones, pravastatin (40 mg twice a day) or placebo was randomly administered to 16 bile fistula patients for 5 days. Biliary lipid composition was determined in basal conditions and for 5 consecutive days after drug withdrawal. Both biliary cholesterol concentration and saturation increased significantly on the second day after pravastatin withdrawal, but tended to decrease thereafter. Biliary bile acids and phospholipids were not affected. This short-lasting effect on biliary cholesterol excretion was probably the result of a transient increase of hepatic cholesterol synthesis by the up-regulated HMG-CoA reductase in the absence of the inhibitory drug. These results are consistent with the hypothesis that, also in humans, biliary cholesterol excretion could be dependent on the hepatic free cholesterol pool.

The relationship between the Spine Deformity Index, biochemical parameters of bone metabolism and vascular calcifications: results from the Epidemiological VERtebral FRACtures iTalian Study (EVERFRACT) in dialysis patients.

Abstract Background: The Spine Deformity Index (SDI) is a measure of vertebral fractures (VFs), providing information on both their number and severity. Methods: We evaluated the relationships between SDI and clinical, biochemical and arterial calcification parameters in 387 hemodialysis (HD) patients. VFs, assessed by quantitative vertebral morphometry, and vascular calcifications were identified in the same lateral spinal X-ray. To improve the detection of fracture severity, we created a corrected SDI (c-SDI), by dividing SDI for the number of VFs. We assessed routine biochemistry, bone-Gla-protein (BGP), undercaboxylated BGP (ucBGP), and matrix-Gla-protein (MGP). Results: VFs prevalence was 55.3%. HD patients with a SDI >1 were more frequently males (p<0.05), and had lower BGP (p<0.01). Patients with a c-SDI >1 had higher LDL-cholesterol (p<0.05) and lower ucBGP (p<0.05) and MGP (p<0.05). Calcifications of the abdominal aorta (AAoC) were more frequent in patients with SDI >1 (p<0.05) and with c-SDI >1 (p<0.05). Multivariate logistic regression showed that male sex (OR 1.86, CI 1.20–2.91), age (OR 1.03, CI 1.01–1.05) and albumin ≥3.5 g/dL (OR 0.54, CI 0.31–0.93) were predictors of a SDI >1. Age (OR 1.05, CI 1.03–1.07), LDL-cholesterol (OR 1.74, CI 1.04–2.92) and ucBGP (OR 0.35, CI 0.18–0.70) were associated with c-SDI >1. Conclusions: We conclude that the severity of VFs was associated with age, atherogenic factors and bone metabolism markers.

The effect of risedronate on osteogenic lineage is mediated by cyclooxygenase-2 gene upregulation.

IntroductionThe purpose of this study was to evaluate the effects of risedronate (Ris) in the modulation of bone formation in rats with glucocorticoid (GC)-induced osteoporosis by histomorphometric, immunohistochemical and gene expression analyses.MethodsWe analyzed structure, turnover and microarchitecture, cyclooxygenase 2 (COX-2) levels and osteocyte apoptosis in 40 female rats divided as follows: 1) vehicle of methylprednisolone (vGC) + vehicle of risedronate (vRis); 2) Ris 5 μg/Kg + vGC; 3) methylprednisolone (GC) 7 mg/Kg + vRis; 4) GC 7 mg/Kg +Ris 5 μg/Kg. In addition, we evaluated cell proliferation and expression of COX-2 and bone alkaline phosphatase (b-ALP) genes in bone marrow cells and MLO-y4 osteocytes treated with Ris alone or in co-treatment with the selective COX-2 inhibitor NS-398 or with dexametasone.ResultsRis reduced apoptosis induced by GC of osteocytes (41% vs 86%, P < 0.0001) and increased COX-2 expression with respect to controls (Immuno-Hystochemical Score (IHS): 8.75 vs 1.00, P < 0.0001). These positive effects of Ris in bone formation were confirmed by in vitro data as the viability and expression of b-ALP gene in bone marrow cells resulted increased in a dose dependent manner.ConclusionsThese findings suggest a positive effect of Ris in bone formation and support the hypothesis that the up-regulation of COX-2 could be an additional mechanism of anabolic effect of Ris.