Antonino Bono

Low vitamin D serum level is related to severe fibrosis and low responsiveness to interferon‐based therapy in genotype 1 chronic hepatitis C

25‐Hydroxyvitamin D (25[OH]D) can potentially interfere with inflammatory response and fibrogenesis. Its role in disease progression in chronic hepatitis C (CHC) and its relation with histological and sustained virological response (SVR) to therapy are unknown. One hundred ninety‐seven patients with biopsy‐proven genotype 1 (G1) CHC and 49 healthy subjects matched by age and sex were consecutively evaluated. One hundred sixty‐seven patients underwent antiviral therapy with pegylated interferon plus ribavirin. The 25(OH)D serum levels were measured by high‐pressure liquid chromatography. Tissue expression of cytochrome (CY) P27A1 and CYP2R1, liver 25‐hydroxylating enzymes, were assessed by immunochemistry in 34 patients with CHC, and in eight controls. The 25(OH)D serum levels were significantly lower in CHC than in controls (25.07 ± 9.92 μg/L versus 43.06 ± 10.19; P < 0.001). Lower levels of 25(OH)D were independently linked to female sex (P = 0.007) and necroinflammation (P = 0.04) by linear regression analysis. CYP27A1, but not CYP2R1, was directly related to 25(OH)D levels (P = 0.01), and inversely to necroinflammation (P = 0.01). Low 25(OH)D (odds ratio [OR], 0.942; 95% confidence interval [CI], 0.893–0.994) and cholesterol (OR, 0.981; 95%CI, 0.969–0.992) levels, older age (OR, 1.043; 95%CI, 1.002–1.085), high ferritin (OR, 1.003; 95%CI, 1.001–1.005), and necroinflammation (OR, 2.235; 95%CI, 1.014–4.929) were independently associated with severe fibrosis (F3–F4) by multivariate logistic analysis. Seventy patients (41%) achieved SVR. By multivariate analysis, hepatic steatosis (OR, 0.971; 95%CI, 0.944–0.999), lower cholesterol (OR, 1.009; 95% CI, 1.000–1.018), and 25(OH)D levels (OR, 1.039; 95%CI, 1.002–1.077) were independently associated with no SVR. Conclusion: G1 CHC patients had low 25(OH)D serum levels, possibly because of reduced CYP27A1 expression. Low vitamin D is linked to severe fibrosis and low SVR on interferon (IFN)‐based therapy. (HEPATOLOGY 2010.)

Blood lipids, homocysteine, stress factors, and vitamins in clinically stable multiple sclerosis patients

Multiple Sclerosis (MS) patients present a decrease of antioxidants and neuroprotective and immunoregulatory vitamins and an increase of total homocysteine (tHcy), cholesterol (CHL), HDL-cholesterol, and of cellular stress markers, variably associated with the different phases of the disease. We compared the blood levels of uric acid, folic acid, vitamins B12, A, and E, tHcy, CHL, HDL-cholesterol, and triglycerides in forty MS patients during a phase of clinical inactivity with those of eighty healthy controls, matched for age and sex. We found higher levels of tHcy (p = 0.032) and of HDL-cholesterol (p = 0.001) and lower levels of vitamin E (p = 0.001) and the ratio vitamin E/CHL (p = 0.001) in MS patients. In conclusion, modifications of some biochemical markers of cell damage were detected in MS patients during a phase of clinical inactivity.

Retinoid dynamics in chicken eye during pre-and postnatal development

Changes in the steady state level of retinols, retinaldehydes and retinyl esters in the trans and 11-cis forms and trans retinoic acid were measured in whole chicken eye during development from day 6in ovo to day 3 post-hatch. These retinoids, quantified by different HPLC systems, were detected in this time sequence: trans-retinol and trans-retinyl esters in the first weekin ovo, 11-cis-retinol in the second week. The highest level of 11-cis-retinaldehyde and 11-cis-retinyl esters was reached at the end of developmentin ovo; however, their levels increased further after hatching. The retinoic acid level decreased at the end of the first week, rising again at the end of the second week.The enzyme activities involved in the metabolism of these retinoids-acyl-CoA: retinol acyltransferase, trans-retinol dehydrogenase, 11-cis-retinol dehydrogenase, trans-retinyl ester hydrolase and trans: 11-cis-retinol isomerase were also estimated and they were detectable already in the first week of developmentin ovo.At day 6 of the biosynthesis of retinoic acid by the retinaldehyde dehydrogenase activity from retina cytosol was also shown.

Modulation by Docosahexaenoic Acid of the Epinephrine-Stimulated Adenylate Cyclase Activity of the Bovine Retina

Abstract: This work shows that unsaturated fatty acids enhance the epinephrine‐stimulated adenylate cyclase activity in bovine retina. The modulating effect on the epinephrine‐stimulated formation of cyclic AMP seems to be linked to the degree of unsaturation of the fatty acid. Treatment of the intact retina with docosahexaenoic acid in the concentration range 0.5 × 10‐6‐l × 10‐3M does not affect the enzyme activity measured in the absence of the hormone but markedly increases the cyclase activity when the tissue is incubated in the presence of 0.1 mM epineph‐rine. Docosahexaenoic acid enhances the maximal response to epinephrine without affecting the apparent ED50 value for this effector. Docosahexaenoic acid at 0.5 mM also increases the hormone‐stimulated adenylate cyclase activity in retinal cell‐free homogenate, whereas it has no effect on the epinephrine‐sensitive enzyme solubilized from the membrane fraction with 1% Triton X‐305. When docosahexaenoic acid‐preincubated intact retina and cell‐free Homogenate are incubated in the presence of defatted albumin, both the observed activating effect of the fatty acid on the epinephrine‐stimulated adenylate cyclase activity and the enhancement of the enzyme response to the hormone significantly diminish.

Binding of 11-cis retinaldehyde to the partially purified cellular retinaldehyde binding protein from bovine retinal pigment epithelium.

11-cis retinaldehyde binding analysis was performed on a bovine retinal pigment epithelium preparation of cellular retinaldehyde binding protein (CRALBP), whose purity degree was estimated as 75%. Equilibrium binding studies were carried out measuring the replacement of tritium-labeled with unlabeled 11-cis retinaldehyde at 25°C. Analysis of the experimental data both by a direct curve-fitting procedure utilizing a non linear least square regression analysis and by a conventional Scatchard plot revealed a single non-interacting binding site with an apparent equilibrium constant of 0.9×10−7 M. A binding stoichiometry of approximately 1 mol of 11-cis retinaldehyde/mol of binding protein can be calculated from the experimental data. Competition studies carried out in the presence of unlabeled ‘trans’ and ‘cis’ isomers of Vitamin A derivatives confirm the high degree of specificity of the 11-cis retinaldehyde binding.

Vitamin D receptor gene polymorphisms and plasma renin activity in essential hypertensive individuals

Several studies analyzed 25-hydroxyvitamin D (25[OH]D) and blood pressure (BP) relationship with mixed results. Moreover, a relationship between the risk of hypertension and vitamin D receptor (VDR) gene polymorphisms, FokI and BsmI, was reported. This study was aimed to analyze these relationships in essential hypertensive (EH) patients. Seventy-one EH patients, 18–75 years old, were enrolled. Patients underwent clinical BP, 24-h ambulatory BP monitoring, 25[OH]D and plasma renin activity (PRA) evaluations. FokI and BsmI VDR polymorphisms were analyzed and compared with those of 72 healthy controls. In EH patients, the median 25[OH]D levels were lower than 30 ng ml−1. We found a significant negative correlation between 25[OH]D and 24-h systolic BP (r=−0.277, P=0.043). This correlation persisted in backward stepwise multivariate analyses (β=−0.337; P=0.022), after adjustment for age, gender, body mass index, glomerular filtration rate, and PRA. We did not observe statistically significant correlation between 25[OH]D and PRA. We compared the allelic frequencies and genotype distribution between patients and controls, and FokI and BsmI VDR polymorphisms were not associated either with hypertensive status or with PRA. Further wide studies are needed to clarify this relationship.

Correlation between the effects of retinoic acid and dexamethasone on liver tyrosine aminotransferase.

A single dose of 50 microg of trans-retinoic acid administered to rats significantly raised the level of hepatic tyrosine after a few hours. This effect was compared with that of dexamethasone and a possible correlation between these effectors was also investigated. An equal increase in enzyme activity level caused by retinoic acid was observed in adrenalectomized rats, leading to the suggestion that the effect of retinoic acid on liver tyrosine aminotransferase is independent of glucocorticoids. However, the study of the binding activity of the liver nuclear glucocorticoid receptors vs dexamethasone showed that this activity is favoured by retinoic acid, whereas no variation was evidenced for retinoic acid receptors caused by dexamethasone. In the adrenalectomized rat, the synergistic effect produced by the association of retinoic acid and dexamethasone at the lowest doses used led us to conclude that retinoic acid is an efficient effector of liver tyrosine aminotransferase. It probably affects tyrosine aminotransferase activity in a dependent and an independent way, regulated respectively by the glucorticoid status and by the provision of retinoic acid.

Analysis of a soluble lipid-protein complex carrying endogenous 11-cis retinaldehyde from bovine retinal pigment epithelium

SummaryA soluble lipid-protein complex in bovine retinal pigment epithelium is shown to carry endogenous 11-cis retinaldehyde, in the extent of 15% of the total 11-cis retinaldehyde found in this tissue. The complex, analyzed with respect to its chemical composition, exhibits a lipid composition close resembling the lipid composition of the rod outer segment membrane; the SDS-PAGE evidences the presence of a number of protein bands, two of which of 34 and 27 kDa appear glycoproteins. Finally, the lipid-protein complex exhibits a discrete level of a Cathepsin D-like protease activity. From the above, the possibility is discussed that the soluble lipid-protein complex could represent some phagolysosomal inclusion occurring in the pigment epithelial cells upon rod outer segment phagocytosis.