Antonella Ruello

Cold Pressor Test Raises Serum Concentrations of ICAM-1, VCAM-1, and E-Selectin in Normotensive and Hypertensive Patients

In patients with essential hypertension, elevated soluble E-selectin (sE-selectin) levels may indicate endothelial cell injury or activation. We therefore sought to ascertain whether arterial blood pressure increased by the cold pressor test can modify serum concentrations of sE-selectin and other soluble forms of adhesion molecules, such as soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1), or the expression of any adhesion molecules in circulating monocytes and lymphocytes. Our findings show that levels of sE-selectin, sVCAM-1, and sICAM-1 are higher in patients with essential hypertension than in normotensive subjects (sICAM-1, 380 +/- 52 versus 262 +/- 96 ng/mL, P<.05; sVCAM-1, 720 +/- 52 versus 625 +/- 38 ng/mL, P<.05; and sE-selectin, 75 +/- 21 versus 61 +/- 22 ng/mL, P<.05). Furthermore, in normotensive and hypertensive patients, the cold pressor test caused an increase in serum concentrations of sICAM-1, sVCAM-1, and sE-selectin, but it did not cause changes in the expression of adhesion molecules in circulating monocytes and lymphocytes. High arterial blood pressure may therefore increase the production of serum adhesion molecules, probably through endothelial activation.

Effects of homocysteine on proliferation, necrosis, and apoptosis of vascular smooth muscle cells in culture and influence of folic acid.

BACKGROUND It is known that hyperhomocysteinemia is associated with an increased risk of vascular disease, yet little is known about the pathogenic mechanisms underlying the action of homocysteine (Hcy) itself. METHODS We evaluated the effects of Hcy on cell proliferation, apoptosis, and necrosis in smooth muscle cells (SMCs) cultured for 24 h with different amounts of Hcy. The percentage of apoptotic and necrotic cells from the culture was evaluated using two different techniques: annexin V-FITC and propidium iodide (PI) fluorescence and apoptosis TUNEL assay. RESULTS The addition of 10 microM/l of Hcy to the medium was followed by a significant increase in cell proliferation and death, through apoptosis and necrosis, respectively. Notwithstanding this apparent balance, a significant increase was found in the total number of cells present in Hcy-treated culture, thus demonstrating a positive dose-dependent correlation with Hcy concentrations in the culture medium. The addition of folic acid to the culture medium significantly reduced both Hcy concentrations in media and the effects of Hcy on the proliferation/apoptosis/necrosis balance of cells in culture. The percentages for apoptotic cells and for cells with a necrotic morphology continued to increase as Hcy concentrations increased, although the absolute values were lower in the culture treated than in that not treated with folic acid. CONCLUSIONS In the presence of folic acid, at increasing concentrations of Hcy, the total number of cells in culture showed increases far less relevant with respect to the control. Also the percentage of apoptotic cells to that of cells with a necrotic morphology, although conserving the tendency to increase to growth of the concentrations of Hcy, have shown absolute values that were lower in the folic acid-treated cultures.

Interleukin-18 and CD30 serum levels in patients with moderate-severe depression

Interleukin-18 (IL-18), a pro-inflammatory cytokine that plays an important role in the T-cell-helper type 1 response, is a new member of the family of cytokines produced in the brain. CD30 is a marker of T-cell-helper type 2 lymphocytes. We evaluated IL-18 and CD30 serum levels in 10 patients affected by moderate-severe depression (MSD). We demonstrated for the first time that serum IL-18 levels of MSD patients were significantly higher than those of healthy donors. On the contrary, no significant difference was found between serum CD30 levels of MSD patients compared with those of healthy donors. These data strengthen the hypothesis that MSD disease is associated with an inflammatory response, mainly T-cell-helper type 1, and suggest an important role for IL-18 in the pathophysiology of MSD.

Urinary Excretion of Aquaporin-2 Water Channel During Pregnancy

BACKGROUND: In healthy primiparas the total body water content increases by about 8 liters within the last trimester, with a consequent reduction in plasma arginine-vasopressin (AVP) levels. The aim of the present study was to investigate the effect of normal pregnancy on urinary excretion of AQP2, a vasopressin sensitive water channel.METHODS: Forty-five healthy pregnant primiparas (specify mean age and range) with a physiological single-fetus pregnancy were studied during weeks 12, 24 and 36 of pregnancy and then for 3 to 5 days postpartum. The control group consisted of 14 age-matched women in the early follicular phase of the menstrual cycle (day 5 or 6). The behavior of plasma AVP, ANP, oxytocin, urinary 6-keto-PGF1α (a metabolite of prostacyclin) and urinary AQP-2 excretion were evaluated in all subjects.RESULTS: Plasma ANP and oxytocin, and urinary AQP-2 and 6kPGF1α excretion increased during all three trimesters, with the highest peaks at the 36th week. In the postpartum period, these values markedly decreased. No statistically significant changes were found in plasma AVP levels throughout the study period.CONCLUSIONS: Our findings suggest that a non-AVP factor present in pregnancy plays a role in the control of the excretion of AQP-2 water channels.

Effect of interleukin 8 and ICAM-1 on calcium-dependent outflow of K+ in erythrocytes from subjects with essential hypertension.

SUMMARY Introduction: The pathogenic mechanisms underlying the increase in peripheral resistance and the contraction of smooth muscular fibre cells in essential hypertension are not yet clearly understood. However, it is now known that immune system activation plays a role in the pathogenesis of some forms of arterial hypertension, and recent data show that the Ca2+ influx in some cells (i.e. red blood cells, leukocytes, platelets, smooth muscular fibre cells) is increased in subjects with essential hypertension, thus revealing a possible alteration in cellular membrane. The end-points of this study were therefore to ascertain whether red blood cells used as a cellular membrane model have a greater Ca2+ dependent K+ flow (Gardos effect) in hypertensive patients than in normotensive controls, to point out a different regulation of ionic channels, and whether IL-8 and the adhesion molecule ICAM-1 influence the membranous outflow. Material and methods: The study was conducted on 87 Caucasian subjects. Of these, 50 (25 men, 25 women; mean age 43 ± 3 years, mean body mass index (BMI) 27 ± 0.5 and 22.3 ± 0.3 kg m2, respectively) had mild-to-moderate hypertension (mean arterial blood pressure 120±8mmHg).The other 37 (18 men, 19 women; mean age 39 ± 3 years; BMI 23.8 ± 0.5 kg m2 and 22.8 ± 0.5 kg m2, respectively were normotensive healthy volunteers (mean arterial blood pressure 89 ± 2 mm Hg).All the patients and subjects were untreated for at least 4 weeks before blood sampling. Results: Ca2+-dependent K+ outflow was found to be greater in samples from patients with essential hypertension than in those from normotensive controls. lL-8 and ICAM-1 significantly enhanced the Ca2+-dependent K+ outflow in red blood cells from hypertensive subjects but had an inhibitory effect on cells from controls. In the experimental model, the presence of TMB-8, a membrane calcium antagonist, significantly reduced the Ca2+-dependent K+ efflux. Conclusion: Vasoconstriction in subjects with essential hypertension may therefore depend on a different regulation of ionic flow that probably supports an increased Ca2+ inflow in smooth muscle fibre cells. Under certain pathological conditions, some immune system components (i.e. interleukins, adhesion molecules) may directly enhance membrane permeability to Ca2+, thus inducing vasoconstriction in the smooth muscle cells.

Relationship between IL-18 and sICAM-1 serum levels in patients affected by coeliac disease: preliminary considerations

OBJECTIVES Cytokine production from activated T cells play a pathogenetic role in mucosal lesions of coeliac disease (CD). Active interleukin (IL)-18 is expressed in the small intestinal mucosa in CD but not in healthy controls. IL-18 enhances intercellular adhesion molecule-1 (ICAM-1) expression. We analyzed IL-18 serum levels in CD patients before and after gluten-free diet and the possible correlation with soluble ICAM-1 (sICAM-1) serum levels. METHODS The study comprises ten CD patients before and after gluten free diet and ten healthy controls. Serum IL-18 and sICAM-1 levels were assayed by immunoenzymatic methods. RESULTS Serum IL-18 and sICAM-1 levels were significantly higher in patients with CD before diet with respect to healthy controls (P<0.05), with a highly significant correlation between the two parameters (Rho=0.800, P=0.0167). Gluten free diet significantly reduces IL-18 and sICAM-1. CONCLUSION Our findings show that IL-18 serum concentrations correlated with the clinical status of CD patients suggesting a role for this cytokine in the pathophysiology of this disease.

Osteoprotegerin and bone mineral density in hemodiafiltration patients.

A newly identified cytokine, osteoprotegerin (OPG) appears to be involved in the regulation of bone remodeling. In vitro studies suggest that OPG, a soluble member of the TNF receptor family of proteins, inhibits osteoclastogenesis by interrupting the intercellular signaling between osteoblastic stromal cells and osteoclast progenitors. As patients with chronic renal failure (CRF) often have renal osteodystrophy (ROD), we investigated the role of osteoprotegerin (OPG) in ROD, and investigated whether there was any relationship between serum OPG, intact parathyroid (PTH) (iPTH), vitamin D, and trabecular bone. Serum OPG combined with iPTH might be a useful tool in the noninvasive diagnosis of ROD, at least in cases in which the range of PTH values compromises reliable diagnosis. Thirty-six patients on maintenance hemodiafiltration (HDF) and a control group of 36 age and sex matched healthy subjects with no known metabolic bone disease were studied. The following assays were made on serum: iPTH, osteocalcin (BGP), bone alkaline phosphatase, 25(OH)-cholecalciferol, calcium, phosphate, OPG, IGF-1, estradiol, and free testosterone. Serum Ca+ +, P, B-ALP, BGP, IGF-1, iPTH, and OPG levels were significantly higher in HDF patients than in controls, while DXA measurements and quantitative ultrasound (QUS) parameters were significantly lower. On grouping patients according to their mean OPG levels, we observed significantly lower serum IGF-1, vitamin D3 concentrations, and lumbar spine and hip bone mineral density in the high OPG groups. No correlation was found between OPG and bone turnover markers, whereas a negative correlation was found between serum OPG and IGF-1 levels (r= − 0.64, p = 0.032). Serum iPTH concentrations were positively correlated with bone alkaline phosphatase (B-ALP) (r = 0.69, p = 0.038) and BGP (r = 0.92, p < 0.001). The findings made suggest that an increase in OPG levels may be a compensatory response to elevated bone loss. The low bone mineral density (BMD) levels found in the high OPG group might have been due to the significant decrease in serum IGF-1 and vitamin D3 observed. In conclusion, the findings made in the present study demonstrate that increased OPG in hemodiafiltration patients is only partly due to decreased renal clearance. As it may partly reflect a compensatory response to increased bone loss, this parameter might be helpful in the identification of patients with a marked reduction in trabecular BMD.

Effect of a Prostacyclin Analogue, Iloprost, on Urinary Aquaporin-2 Excretion in Humans

The regulation of aquaporin-2 (AQP2) water channel excretion in the collecting duct depends mainly on the action of vasopressin (AVP). Recently, however, other regulatory factors have been identified: atrial natriuretic factor, oxytocin and prostaglandins. In healthy volunteers (5 males, 5 females; mean age 23 ± 3 years) we therefore evaluated the effect of a stable analogue of prostacyclin-2 (PGI2), iloprost, on renal function and on the urinary excretion of AQP2 (U-AQP2). After 6 h of iloprost infusion, U-AQP2 increased from 0.8 ± 0.15 to 1.8 ± 0.2 pmol/mg creatinine (p < 0.001), while the urinary flow rate increased from 1.4 ± 0.2 to 1.8 ± 4 (p < 0.01). No significant change was found in the AVP serum concentration, with a basal value of 3.17 ± 0.12 vs. 3.15 ± 0.12 pg/ml after 6 h of prostacyclin infusion. All the values returned to pre-study levels after a recovery period of 6 h. In conclusion, the PGI2 analogue, iloprost, can induce U-AQP2 excretion independent of AVP.

In vitro interleukin-8 production by monocytes treated with lithium chloride from breast cancer patients.

Aims and background Since interleukin-8 (IL-8) has a suppressive effect on hematopoiesis, lithium induces leukocytosis and granulocytosis and mononuclear cells are defective in patients affected by neoplastic disease, we analyzed IL-8 production by monocytes obtained from patients with non-metastatic breast cancer (BCaMO) and metastatic breast cancer (BCaM1) and the effect of lithium chloride (LiCI) on these cells. Lithium salt compounds are used to limit the degree and duration of neutropenia in patients receiving chemotherapy for cancer and acute leukemia. Lithium influences the hematopoietic system, which is known to be regulated by numerous cytokines including IL-8. Methods We selected three groups of subjects (15 per group): patients affected by BCaMO, BCaM1 and healthy donors (HD) matched for sex and age. IL-8 release was assessed in supernatants of lipopolysaccharide (LPS) and/or LiCI-treated monocyte cultures. Results Monocytes from BCaM1 released higher IL-8 levels than monocytes from BCaMO (P <0.0001); the IL-8 levels of both groups were significantly higher (P <0.0001) than those of HD. In vitro LiCI treatment reduced IL-8 production by monocytes obtained from all subjects compared to the same cells when untreated or LPS treated. The suppressive effect of LiCI on IL-8 production by monocytes from breast cancer patients was particularly marked in monocytes from BCaMO with respect to those from BCaM1. LPS treatment increased the IL-8 production more in BCaM1 monocytes than in BCaMO monocytes. Moreover, combined LPS/LiCI treatment of monocytes significantly (P <0.0001) downregulated the release of IL-8 compared to treatment with LPS alone. Conclusions Our data demonstrate that monocytes from BCaM1 release larger amounts of IL-8 than monocytes from BCaMO and from HD. Lithium was able to downregulate IL-8 production by monocytes from different subgroups. Further studies are needed to clarify if the improvement of the hematopoietic system in vivo observed following lithium therapy could reside, at least in part, in the ability of lithium to downregulate this chemokine.

Reduced bcl-2 concentrations in hypertensive patients after lisinopril or nifedipine administration

In 30 patients with essential hypertension and 30 healthy control subjects, we evaluated blood concentrations of B cell leukemia-2 (bcl-2), a protooncogene that can reduce apoptosis. Bcl-2 concentrations were higher in hypertensive than in normotensive subjects. The increase in pressure due to a cold pressor test caused a further increase in blood bcl-2 concentrations, in both hypertensive and normotensive subjects. Treatment of hypertensive patients with hypotensive drugs caused a reduction in bcl-2 concentrations, which was more marked after administration of lisinopril than of nifedipine. The results suggest that concentrations of bcl-2 are increased in patients with hypertension, which could be an important factor in cell proliferation underlying posthypertensive vascular remodeling. Moreover, lisinopril and nifedipine appear to be capable of reducing bcl-2 concentrations, with potentially beneficial effects on vascular modifications in patients with hypertension.