Bartolomeo Farzati

Circulating Adhesion Molecules in Humans Role of Hyperglycemia and Hyperinsulinemia

BACKGROUND We assessed the role of glucose and insulin in the regulation of circulating levels of soluble intercellular adhesion molecule-1 (sICAM-1) and vascular adhesion molecule-1 (sVCAM-1) in normal subjects and in patients with type 2 diabetes. METHODS AND RESULTS Plasma glucose concentrations were acutely raised in 10 normal subjects and 10 newly diagnosed, complication-free type 2 diabetic patients and maintained at 15 mmol/L for 2 hours. In normal subjects, plasma sICAM-1, but not sVCAM-1, levels rose significantly (P<0.01) at 1 hour and returned to basal values at 2 hours. In another study, octreotide was infused during the hyperglycemic clamp to block the release of endogenous insulin; this prevented the late fall of plasma sICAM-l levels observed in under control clamp conditions. The diabetic patients had plasma sICAM-1 levels significantly higher (P<0.01) than those of the control subjects; plasma sVCAM-1 levels were similar. Both sICAM-l and sVCAM-1 concentrations did not change significantly during the control hyperglycemic clamp; however, octreotide infusion increased plasma sICAM-1 levels, which remained significantly (P<0.05) above baseline during the whole clamp. In an additional 10 type 2 diabetic patients, overnight euglycemia (plasma glucose 5.5 mmol/L) obtained with the aid of an artificial pancreas or supplementation with l-arginine (10 g PO for 30 days), the natural precursor of NO, normalized the increased plasma sICAM-1 levels. CONCLUSIONS Acute hyperglycemia increases circulating sICAM-1 levels in normal subjects, whereas the correction of hyperglycemia with insulin or l-arginine supplementation restored to normal levels the increased plasma sICAM-1 levels of type 2 diabetic patients.

High glucose downregulates endothelial progenitor cell number via SIRT1

Increasing evidence indicates that mammalian SIRT1 mediates calorie restriction and influences lifespan regulating a number of biological molecules such as FoxO1. SIRT1 controls the angiogenic activity of endothelial cells via deacetylation of FoxO1. Endothelial dysfunction and reduced new blood vessel growth in diabetes involve a decreased bioactivity of endothelial progenitor cells (EPCs) via repression of FoxO1 transcriptional activity. The relative contribution of SIRT1 with respect to the direct effects of high glucose on EPC number is poorly understood. We report that treatment of EPCs with high glucose for 3 days determined a consistent downregulation of EPC positive to DiLDL/lectin staining and, interestingly, this was associated with reduced SIRT1 expression levels and enzyme activity, and increased acetyl-FoxO1 expression levels. Moreover, EPCs responded to high glucose with major changes in the expression levels of cell metabolism-, cell cycle-, and oxidative stress-related genes or proteins. Proteomic analysis shows increased expression of nicotinamide phosphoribosyl transferase and mitochondrial superoxide dismutase whereas a glucose-related heat shock protein is reduced. These findings show that SIRT1 is a critical modulator of EPCs dysfunction during alteration of glucose metabolism.

Peripheral Blood T Lymphocytes from Systemic Sclerosis Patients Show Both Th1 and Th2 Activation

Our objective was to investigate the phenotype of helper T cells in the peripheral blood of patients with systemic sclerosis (SSc). PBMC from 15 patients with SSc and 15 sex- and age-matched controls were investigated for lymphocyte subpopulations (CD3, CD4, CD8, CD19, CD16/CD56, CD3-DR); IL-2, IL-4, and IFN-γ mRNAs; and the relative cytokines in their cytoplasm. The last assay was carried out both in unstimulated and in PMA-activated PBMC. SSc patients presented a higher percentage of activated T cells, CD3+ DR+ (19.7 ± 9.9 vs 5.1 ± 2.5%; P < 0.0001); 12 of them presented IFN-γ mRNA-positive cells; and none IL-2 or IL-4 mRNAs. Under basal conditions, PBMC from six SSc patients contained IL-2, IL-4, and IFN-γ (i.e., they showed both Th1 and Th2 activation), and 1 IFN-γ only. PMA-stimulated PBMC of patients differed from those of controls only in the increased percentage of IFN-γ positive cells (52 ± 12 vs 37 ± 11%; P < 0.01). Our study demonstrates that Th1 activation occurs in the peripheral blood of SSc patients. This evidence must be faced with from both a pathogenetic and a therapeutical point of view.

Beneficial effects of autologous bone marrow cell infusion and antioxidants/L-arginine in patients with chronic critical limb ischemia.

Background Short-term (within 6 weeks follow-up) clinical studies indicate that implantation of bone marrow cells (BMCs) into ischemic limbs may improve peripheral ischemia. Here, the long-term safety and feasibility of intraarterial autologous BMCs with oral treatment with antioxidants and L-arginine were investigated in patients with critical ischemia on account of advanced atherosclerotic peripheral arterial disease (PAD). Methods Eighteen patients with PAD (advanced III/IV Fontaine stages) were enrolled in this study (NCT00306085). An additional group of 18 patients taking maximal drug therapy that refused BMC therapy served as control. The BMC-treated group received two doses of BMCs in the leg arteries (time 0 and 45 days). After 30 days from the first BMC dose, patients received daily antioxidants, and l-arginine. Therapeutic neoangiogenesis was estimated by angiography and laser Doppler capillaroscopy. Results Ankle brachial index improvement (ΔABI: >0.1) was seen in 10 patients at 3 months and in 12 patients at 12–18 months. Ischemic ulcers improved in 13 patients (after 6–12 months). Although two patients underwent amputation, the mean maximum walking distance significantly increased at 3 months and was sustained up to 18 months. Among conservative patients, 10 underwent amputation in comparison with two BMC-treated patients (55.6 vs. 13.3%; P = 0.014). Conclusion This small study shows that intraarterial autologous BMC and antioxidants and l-arginine therapy is safe and effective in patients with advanced atherosclerotic PAD with positive effects until 18 months. Eur J Cardiovasc Prev Rehabil 15:709–718

Functional impairment of hematopoietic progenitor cells in patients with coronary heart disease

The circulating form of endothelial progenitors cells (EPCs) are derivated from bone marrow (BM)‐derived hematopoietic stem cells (HSCs). Enhanced mobilization of EPCs was shown to be linked to cardiac diseases. This study investigated whether reduced EPC levels in advanced coronary heart disease (CHD) are secondary to a functional exhaustion of HSCs in the BM or to reduced mobilization. Number and functional properties of EPCs were assessed in 15 healthy controls, and 40 patients with CHD. The colony‐forming unit (CFU) capacity of BM‐derived mononuclear cells and the CD34+ HSC number were examined in four healthy volunteers, and 15 CHD patients. EPC number was reduced in CHD patients (P < 0.01 vs. controls). Moreover, the migratory capacity was significantly impaired in EPCs of CHD patients (P < 0.05 vs. controls). On multivariate analysis, CHD was an independent predictor of functional EPC impairment. CFUs were reduced in CHD patients (59.6 ± 21.2 vs. 75.4 ± 25.8 in controls, P < 0.05). CHD was also predictor of impaired CFU capacity. In this small clinical study, CHD is associated with selective impairment of HSC function in the BM and in the peripheral blood, which may contribute to impairment of cardiac function.

Antioxidants increase number of progenitor endothelial cells through multiple gene expression pathways

To date, there is no report on the effect of antioxidants on endothelial progenitor cells (EPCs). This study shows that in vitro incubation of EPCs with vitamin C and E reverted the already well documented lowering effect of TNF-α on EPC number and increased p-p38 expression levels. In order to document major changes of gene expression levels and gain insight into signalling pathways, microarray analysis was performed and a significant variation of the expression of 5389 genes in EPCs following antioxidant treatment was detected. Also in vivo evidence is provided about the positive effect of antioxidant vitamins on EPCs, since vitamin C and E supplementation potentiated the physical training-induced increase of EPC number and VEGF levels. Together, these data indicate that antioxidant treatment ameliorates EPC number and causes major changes of gene expression within these cells in vitro. Furthermore, concomitant antioxidant supplementation and physical training in vivo raised the levels of circulating EPCs and serum VEGF more than physical training alone.

Effect of red wine antioxidants and minor polyphenolic constituents on endothelial progenitor cells after physical training in mice

Circulating endothelial progenitor cells (EPCs) play a significant role in regeneration of damaged blood vessels. Levels and functional activities of EPCs are noticeable altered by risk factors for coronary heart disease (CHD) and compounds that can prevent or ameliorate EPC dysfunction are currently of special clinical interest. Here, we evaluate the effects of red wine (RW) on EPCs in C57BL/6J mice subjected to physical exercise. FACS computed counting showed a significant increase of EPC number (P<0.05) in mice after short-term supplementation with RW. VEGF serum concentration was significantly increased by physical training in the presence or absence of RW supplementation (P<0.001). These in vivo observations support previous in vitro observation of the beneficial effect of RW in the modulation of EPC levels.

Detrimental effects of Bartonella henselae are counteracted by L-arginine and nitric oxide in human endothelial progenitor cells.

The recruitment of circulating endothelial progenitor cells (EPCs) might have a beneficial effect on the clinical course of several diseases. Endothelial damage and detachment of endothelial cells are known to occur in infection, tissue ischemia, and sepsis. These detrimental effects in EPCs are unknown. Here we elucidated whether human EPCs internalize Bartonella henselae constituting a circulating niche of the pathogen. B. henselae invades EPCs as shown by gentamicin protection assays and transmission electron microscopy (TEM). Dil-Ac-LDL/lectin double immunostaining and fluorescence-activated cell sorting (FACS) analysis of EPCs revealed EPC bioactivity after infection with B. henselae. Nitric oxide (NO) and its precursor l-arginine (l-arg) exert a plethora of beneficial effects on vascular function and modulation of immune response. Therefore, we tested also the hypothesis that l-arg (1–30 mM) would affect the infection of B. henselae or tumor necrosis factor (TNF) in EPCs. Our data provide evidence that l-arg counteracts detrimental effects induced by TNF or Bartonella infections via NO (confirmed by DETA-NO and L-NMMA experiments) and by modulation of p38 kinase phosphorylation. Microarray analysis indicated several genes involved in immune response were differentially expressed in Bartonella-infected EPCs, whereas these genes returned in steady state when cells were exposed to sustained doses of l-arg. This mechanism may have broad therapeutic applications in tissue ischemia, angiogenesis, immune response, and sepsis.

Effect of L-arginine on circulating endothelial progenitor cells and VEGF after moderate physical training in mice.

Alteration of levels and functional activities of circulating endothelial progenitor cells (EPCs) induced by risk factors for coronary heart disease (CHD) profoundly influence their role in the regeneration of tissue ischemia and angiogenesis. Among antioxidant nutrients in the prevention of CHD, L-arginine is particularly effective in enhancing the protection afforded by moderate physical exercise. Here, we aimed to evaluate the effects of L-arginine on EPC levels in C57BL/6J mice subjected to moderate physical exercise. Results showed that supplementation with L-arginine potentiates the effects of moderate physical exercise by increasing significantly EPCs (P<0.001) and VEGF serum levels (P<0.001). Our report highlights the beneficial effect of l-arginine in the modulation of EPC levels and VEGF secretion.

Effects of transdermal hormone replacement therapy on levels of soluble P- and E-selectin in postmenopausal healthy women

OBJECTIVE To study the adhesion molecule pattern in postmenopausal women who were not receiving hormone replacement therapy (HRT), HRT users, and fertile women. DESIGN Case-control study. SETTING Second University of Naples, Naples, Italy. PATIENT(S) Fifty healthy naturally postmenopausal women and 20 fertile women. INTERVENTION(S) Twenty-six women received no HRT and 24 received continuous transdermal 17 beta-estradiol, 0.05 mg/d, plus oral acetate nomegestrol, 5 mg/d. MAIN OUTCOME MEASURE(S) Levels of the soluble forms of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, and P-selectin. RESULT(S) Women who did not received HRT showed a trend toward higher levels of soluble E-selectin and had significantly higher levels of soluble P-selectin than did fertile women. Levels of soluble E-selectin and soluble P-selectin were significantly lower in HRT users than in nonusers. Levels of VCAM-1 levels were significantly higher in HRT users than in fertile women, but no significant differences in CAM concentrations were found between the other groups. CONCLUSION(S) Menopause may lead to increased levels of soluble E- and soluble P-selectin, whereas long-term HRT is associated with lower selectin concentrations. This suggests that HRT may have a beneficial effect on endothelial function.