Sergio Lario

Mspl identifies a biallelic polymorphism in the promoter region of the α2A‐adrenergic receptor gene

Candidate gene: An increased activity of the sympathetic nervous system has been suggested to play a role in the pathophysiology of essential hypertension ( EHT). However, plasma catecholamine levels are not increased in these patients. An increased density of a,,-adrenergic receptors (a,,-AR) has been reported in patients with EHT (Mores et al. 1990, Calls et al. 1995). The activation of these receptors by epinephrine or norepinephrine promotes peripheral vasoconstriction and salt and water retention. The human cc,,-AR gene is located at 10q23-q25. The complete nucleotide sequence of this gene (HUMADRA2R) has been previously published (Fraser et al. 1989), and two restriction fragment length polymorphisms (DraI and Bsu36I RFLPs) have been reported to date (Hoehe et al. 1988, Sun et al. 1992). A significant association between DraI RFLP and essential hypertension has been described (Lockette et al. 1995, Svetkey et al. 1996), although there is no general agreement on these findings.

Contraction of human hepatic stellate cells activated in culture: A role for voltage-operated calcium channels

BACKGROUND/AIMS Voltage-operated calcium channels are essential for the regulation of vascular tone and are potential targets for vasodilating agents. They regulate calcium entry and thereby cell contraction in vascular cell types. Hepatic stellate cells in the activated phenotype have contractile properties and could participate in the regulation of sinusoidal blood flow. Thus, this study was aimed at investigating the presence of voltage-operated calcium channels in human hepatic stellate cells activated in culture and the effects of their stimulation on intracellular calcium concentration ([Ca2+]i) and cell contractility. METHODS Binding studies using [3H]-nitrendipine were performed to demonstrate the presence of voltage-operated calcium channels. Voltage-operated calcium channels were stimulated by causing cell membrane depolarization either by electrical field stimulation or extracellular high potassium. [Ca2+]i and cell contraction were measured in individual cells loaded with fura-2 using a morphometric method with an epifluorescence microscope coupled to a charge-coupled device-imaging system. RESULTS Binding studies demonstrated the existence of voltage-operated calcium channels in human activated hepatic stellate cells (7.1+/-1.4x10(4) sites/cell with a Kd of 2.1+/-0.1 nM). Both electrical field stimulation and potassium chloride-induced cell depolarization resulted in a marked and prolonged increase in [Ca2+]i followed by intense cell contraction. The degree of cell contraction correlated with the intensity of calcium peaks. Removal of extracellular calcium or preincubation of cells with nitrendipine, a specific antagonist of voltage-operated calcium channels, completely blocked the effects on [Ca2+]i and cell contraction, whereas preincubation of cells with BayK-8644, a specific agonist of voltage-operated calcium channels, increased calcium peaks and contraction. CONCLUSION Activated human hepatic stellate cells have a large number of voltage-operated calcium channels, the activation of which is associated with an increase in [Ca2+]i followed by marked cell contraction. Voltage-operated calcium channels probably play an important role in the regulation of activated hepatic stellate cells contractility.

Expression of transforming growth factor-b1 and hypoxia-inducible factor-1a in an experimental model of kidney transplantation.

Background. Ischemia-reperfusion syndrome has been recognized as an important pathogenic factor in renal transplantation, not only in the development of delayed graft function but also in the development of acute and chronic rejection. Hypoxia-inducible factor (HIF)-1 activates transcription of several genes implicated in cell survival, such as vascular endothelial growth factor (VEGF), and in tissue repair transforming growth factor (TGF)-&bgr;. The purpose of this study was to characterize TGF-&bgr;1, VEGF, and HIF-1&agr; expression profiles during renal transplantation with heart-beating donors (HBD) and non-heart-beating donors (NHBD). Methods. An experimental model of renal transplantation using 40 pairs of large, white, Landrace pigs and including HBD and NHBD was used. Cold-ischemia time was the same in all groups (6 hr), and three groups of NHBD (30, 45, and 90 min) were studied. Immunosuppressive therapy consisted of cyclosporine, except in one HBD group, which was treated with azathioprine. TGF-&bgr;1, VEGF, and HIF-1&agr; expression profiles were performed in renal biopsies obtained at different times: after anesthetic induction (basal); 30, 45, and 90 min after warm ischemia; after cold ischemia; 1 hr after reperfusion; and 5 days after transplantation. Results. TGF-&bgr;1 expression increased after cold ischemia in HBD and remained unaltered during the surgical process in all NHBD groups. HIF-1&agr; and VEGF expression were not greatly modified during surgery in the HBD or NHBD groups. All groups showed a significant increase in TGF-&bgr;1 and HIF-1&agr; expression as well as down-regulation of VEGF 5 days after transplantation, and these effects were independent of immunosuppressive treatment. There were no statistically significant differences among the groups at 5 days after transplantation, although the increase in TGF-&bgr;1 was more pronounced in the HBD groups, especially in azathioprine-treated animals. Conclusions. The initial up-regulation of TGF-&bgr;1 observed in HBD immediately after cold ischemia could have a positive effect on epithelial-tubular regeneration. Warm ischemia has a detrimental effect on TGF-&bgr;1 expression during the early phases of renal transplantation and has no effect on VEGF and HIF-1&agr; expression. The up-regulation of TGF-&bgr;1 and HIF-1&agr; observed after transplantation could have a positive effect on tubular repair. TGF-&bgr;1 expression was lower in animals treated with cyclosporine, probably because of cellular toxicity.

The effects of smoking and its cessation on 8‐epi‐PGF2α and transforming growth factor‐beta 1 in Type 1 diabetes mellitus

Background  Oxidative stress and transforming growth factor‐beta 1 (TGF‐β1) are associated with diabetic complications, and smoking is a risk factor.

Quantifying Plasma Levels of Transforming Growth Factor β1 in Idiopathic Pulmonary Fibrosis

OBJECTIVE Transforming growth factor ss1 (TGF-ss1) is one of the key profibrotic mediators in the pathogenesis of idiopathic pulmonary fibrosis (IPF). The purpose of this study was to investigate the prognostic value of quantifying TGF-ss1 levels in patients with IPF. PATIENTS AND METHODS We conducted a prospective study of 29 IPF patients and 27 healthy controls. Enzyme-linked immunosorbent assays were used to quantify TGF-ss1 levels. RESULTS Mean (SD) TGF-ss1 levels were significantly higher in the IPF patients than in the control subjects (11.1 [7.5] ng/mL vs 4 [2.4] ng/mL; P< .01). Weak inverse correlations were observed between TGF-ss1 levels and both forced vital capacity and total lung capacity. Thirteen IPF patients were evaluated at 8 (1.2) months (range, 5-9 months). The mean TGF-ss1 level was 18.2 (15) ng/mL and there were no significant differences with respect to the initial measurement of 11.1 (7.5) ng/mL. No correlation was observed between changes in respiratory function and changes in TGF-ss1 levels. CONCLUSIONS Although plasma levels of TGF-beta1 were high in the patients with IPF, they do not appear to be a useful prognostic marker of disease activity or therapeutic response.