Riccardo Giunta

Vascular Effects of Acute Hyperglycemia in Humans Are Reversed by l-Arginine Evidence for Reduced Availability of Nitric Oxide During Hyperglycemia

BACKGROUND Acute hyperglycemia may increase vascular tone in normal humans via a glutathione-sensitive, presumably free radical-mediated pathway. The objective of this study was to investigate whether or not the vascular effects of hyperglycemia are related to reduced availability of nitric oxide. METHODS AND RESULTS Acute hyperglycemia (15 mmol/L, 270 mg/dL) was induced in 12 healthy subjects with an artificial pancreas. Systolic and diastolic blood pressures, heart rate, and plasma catecholamines showed significant increases (P < .05) starting after 30 minutes of hyperglycemia; leg blood flow decreased significantly (15%; P < .05) at 60 and 90 minutes. Platelet aggregation to ADP and blood viscosity also showed significant increments (P < .05). The infusion of L-arginine (n = 7, 1 g/min) but not D-arginine (n = 5, 1 g/min) or L-lysine (n = 5, 1 g/min) in the last 30 minutes of the hyperglycemic clamp completely reversed all hemodynamic and rheological changes brought about by hyperglycemia. Infusion of NG-monomethyl-L-arginine (L-NMMA; 2 mg/min) to inhibit endogenous nitric oxide synthesis in 8 normal subjects produced vascular effects qualitatively similar to those of hyperglycemia but quantitatively higher (P < .05); however, heart rate and plasma catecholamine levels decreased during L-NMMA infusion, presumably as a consequence of baroreflex activation. Infusion of L-NMMA during hyperglycemia produced changes not different from those obtained during infusion of L-NMMA alone. CONCLUSIONS The results show that acute hyperglycemia in normal subjects causes significant hemodynamic and rheological changes that are reversed by L-arginine. Moreover, the effects of hyperglycemia are mimicked to a large extent, but not entirely, by infusion of L-NMMA. This suggests that hyperglycemia may reduce nitric oxide availability in humans.

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.

Effects of Perindopril and Carvedilol on Endothelium-Dependent Vascular Functions in Patients With Diabetes and Hypertension

OBJECTIVE To compare the effects of the ACE inhibitor perindopril and the β-blocker carvedilol on blood pressure and endothelial functions in N1DDM patients with hypertension. RESEARCH DESIGN AND METHODS We conducted a double-blind randomized trial in 26 patients with NIDDM and mild hypertension. A 4-week run-in placebo period preceded the active 12-week treatment with perindopril (4–8 mg daily) or carvedilol (25–50 mg daily). Endothelial functions were assessed by evaluating the hemodynamic (mean blood pressure, leg blood flow) and rheological (platelet aggregation, blood viscosity, and blood filterability) responses to an intravenous bolus of 3 g L-arginine, the natural precursor of nitric oxide. RESULTS Both perindopril and carvedilol significantly reduced mean blood pressure (P < 0.001) and increased leg blood flow (P < 0.05) to the same extent; blood filterability remained unchanged in both perindopril- and carvedilol-treated groups. Carvedilol reduced platelet aggregation and blood viscosity significantly (P < 0.05) but perindopril did not. Before treatment, the hemodynamic and rheologic responses to L-arginine were significantly lower in patients (P < 0.05–0.01) than in 20 nondiabetic nonhypertensive control subjects. After 12 weeks of treatment, both drugs normalized the hemodynamic responses to L-arginine. Platelet aggregation response to L-arginine was ameliorated by carvedilol and remained unchanged in the perindopril group. CONCLUSIONS At the doses used, both drugs effectively reduce blood pressure and normalize the hemodynamic responses to L-arginine. The implications of the ameliorated endothelial function for the poor cardiovascular outlook of the NIDDM hypertensive patient need further assessment.

The Squatting Test: A Useful Tool to Assess Both Parasympathetic and Sympathetic Involvement of the Cardiovascular Autonomic Neuropathy in Diabetes

The heart rate responses observed after both squatting and standing are thought to be of reflex nature and may be useful to assess the functional integrity of parasympathetic and sympathetic nerves in diabetes. In the standard maneuver, each subject stood still for 3 min, then squatted down for 1 min, and at last stood up during an inspiratory phase. In 10 healthy subjects (25–31 years of age), lengthening of the R-R interval during squatting was abolished by atropine, whereas propranolol markedly attenuated shortening of the R-R interval at standing from squatting. Squatting test (SqT) ratios (SqT vagal [SqTv] = ratio between the R-R interval mean before squatting and the longest R-R interval after squatting; SqT sympathetic [SqTs] = ratio between the basal R-R interval and the shortest R-R interval at standing) were calculated in 558 healthy subjects and 346 diabetic patients (insulin-dependent diabetes mellitus/non-insulin-dependent diabetes mellitus: 103/243). Normal ranges (95 and 99% confidence intervals [CIs]) for subjects 20–74 years of age showed a statistically significant negative correlation with age. SqTv was outside the 99% CI in 145 (42%) diabetic patients and in 7 (1.3%) of the control subjects. The corresponding figures for SqTs were 40 and 0.8%, respectively. Age and duration of diabetes had a negative influence on SqT ratios. SqT ratios were compared with other reflex tests currently used for diagnosis of autonomic neuropathy: deep breathing (DB), lying-to-standing (LS), Valsalva manuever, and blood pressure change after standing (orthostatic hypotension [OH]). Autonomic involvement was arbitrarily defind as mild (one test pathologica), definite (two tests pathological), or severe (three or more tests pathological), definite (two tests pathological), or severe (three or more tests pathological). In patients with definite or severe involvement, Sqt ratios and DB anf LS tests showed the least overlap between healthy subjects and diabetic patients; however, for patients with mild or no autonomic involvement, SqT rations were significantly better than DB, LS, or OH tests. In conclusion, 1) SqT ratios can discriminate between healthy subjects and diabetic patients to an equal or greater extent than the other tests; 2) SqT ratios give information on both parasympathetic and sympathetic activity; and 3) SqT ratios are better than other single tests in identifying mild autonomic involvement. These results may be important for early intervention trials.

Primary cardiac T-cell lymphoma

Primary cardiac lymphoma (PCL), defined as a lymphoma clinically mimicking cardiac disease, with the bulk of the tumor located intrapericardially, is extremely rare in immunocompetent patients. Clinical manifestations vary depending on sites of involvement in the heart and include chest pain, arrhythmias, pericardial effusion, and heart failure. Diagnosis is often difficult and may require invasive procedures; in some cases, diagnosis is not made until autopsy. Histologically, nearly all cases of PCL reported thus far have been of B-cell origin. In this report, we describe a case of PCL of T-cell origin in an adult immunocompetent patient, the second reported in the literature to the best of our knowledge, and provide a brief overview of the features of previously published PCL cases.

Behavior of Circulating CD4+CD25+Foxp3+ Regulatory T Cells in Colon Cancer Patients Undergoing Surgery

CD4+CD25+Foxp3+ regulatory T cells (Treg) specialize in suppressing immune responses. In this study, 47 consecutive colon cancer patients were subjected to circulating Treg frequency assessment by flow cytometry before and after cancer resection. Thirty-two healthy subjects served as controls. Circulating Treg frequencies were significantly higher in colon cancer patients with respect to healthy controls. When patients were subgrouped according to Dukes stages, a linear relationship was observed between Dukes stages and Treg frequencies. In radically resected patients, Treg frequencies were shown to have significantly dropped down. Patients with advanced colon cancer were more likely to have significantly higher proportions of circulating Treg frequencies than Dukes A and B patients when compared to healthy subjects. Of note, nonradically resected patients were found to display reductions in—but not normalization of—Treg frequencies. These results suggest that cancer itself may be able to drive Treg recruitment as a strategy of immunoevasion.

Effects of preactivated autologous T lymphocytes on CD80, CD86 and CD95 expression by chronic lymphocytic leukemia B cells.

Profound immune dysfunction is a constant feature in B-cell chronic lymphocytic leukemia (B-CLL) patients. Immunological abnormalities include hypogammaglobulinemia, impaired immunoglobulin class switching and diminished germinal center formation. This state of immune suppression renders B-CLL patients highly susceptible to infections, which contribute greatly to morbidity and mortality in this disease. Impaired T cell function in B-CLL is well-documented and has been suggested to result from inhibitory effects exerted by malignant B lymphocytes. Because the presence of leukemic cells may represent a major obstacle to efficient T cell activation, T lymphocytes were separated from CLL B cells, stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin for 4 h, and then cocultured with autologous leukemic B cells both at a 1:1 ratio or at the same ratio as in vivo for 24-40 h. CLL B cell expression of CD86 and CD95 was markedly upregulated using this approach, whereas CD80 expression was augmented only in a minority of patients; these effects were partially preserved even when preactivated T cells were rechallenged with CLL B cells at the same low T/B cell ratio as that observed in vivo. Finally, CD80 upregulation on CLL B cells appeared to be mainly dependent on CD40L-mediated stimulation, whereas CD86 and CD95 expression was efficiently augmented by soluble factors released by preactivated T lymphocytes. In conclusion, efficient activation of T lymphocytes in B-CLL may be achieved which, in turn, may result in enhanced antigen-presenting capacity and susceptibility to apoptosis of leukemic cells via CD86 and CD95 upregulation, respectively.

Detection of Early Sympathetic Cardiovascular Neuropathy by Squatting Test in NIDDM

OBJECTIVE To determine the role of the squatting test in the detection of early sympathetic neuropathy in patients with non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND METHODS Three groups of nonsmoking, nonobese subjects were studied: 10 healthy subjects, 10 NIDDM patients without autonomic neuropathy (AN), and 10 NIDDM patients with AN defined by the presence of a pathological deep-breathing value. All subjects were given three postural tests: lying-to-standing, sitting-to-standing, and squatting test. Heart rate (HR) and finger arterial pressure were recorded with a noninvasive technique. RESULTS Blood pressure (BP) fall (expressed as decremental area) was not significantly different among the groups at standing up after sitting or lying. By contrast, a significantly greater BP drop occurred in NIDDM patients with AN (1,123 ± 245 mm2) compared with NIDDM patients without AN (460 ± 232 mm2) or normal subjects (429 ± 138 mm2, P < 0.001). The HR increase after all the orthostatic maneuvers was smaller in diabetic patients with AN (P < 0.01) compared with that recorded in other groups. Significant correlations were observed between BP fall after squatting and either the expiration:inspiration ratio at deep breathing (r = -0.77, P < 0.001) or the duration of diabetes (r = 0.76, P < 0.001). CONCLUSIONS The intrinsic orthostatic load of the squatting test, which is greater than conventional postural maneuvers, makes the squatting test an easy and useful test to detect early orthostatic dysregulation in NIDDM.

Granulomatous lobular mastitis: another manifestation of systemic lupus erythematosus?

Granulomatous lobular mastitis (GLM) is a benign disease of the breast generally affecting women of child-bearing age. Diagnosis is based on findings of noncaseating granulomatous inflammation at histologic evaluation of biopsy. GLM has been reported in association with infectious diseases (tuberculosis, bacterial, fungal, or parasitic infections), vasculitis (Wegener’s granulomatosis, sarcoidosis, giant cell arteritis, polyarteritis nodosa), foreign body reaction (e.g., breast implants), and oral contraceptive usage. When an apparent etiology cannot be found, GLM is defined as idiopathic. Pathogenesis is unknown, although an abnormal immune response has been hypothesized to underlie the development of this condition. Accordingly, we report here a case of GLM associated with a serological profile indicative of combined systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS), clinically mimicking multifocal breast cancer (Fig. 1). A 65-year-old woman was referred to our Institution because of multiple nodular lesions in both breasts resembling multifocal cancer. Her past medical history was remarkable for a non-ST-elevation myocardial infarction (NSTEMI) occurred at age 40. Relevant laboratory tests included positivity for both ANA (1:1280, homogeneous + nucleolar pattern) and anti-dsDNA (indirect immunofluorescence on Crithidia luciliae), prolonged aPTT (67.7′′), detection of both anticardiolipin IgG (271 GPL U/mL; n.v.: <10) and anti-b2-glycoprotein I IgG (177 UA/mL; n.v.: <10), and consumed complement C4 (8 mg/dL; n.v.: 12– 52). Both patients’ breasts were subjected to excisional biopsy. However, contrary to the initial diagnostic suspicion, the patient was diagnosed as having granulomatous lobular mastitis (Fig. 2). The patient denied clinical complaints attributable to SLE/APS. No pregnancy morbidity/losses were reported during childbearing age. Physical examination was normal, apart from breast involvement. Cultures of breast tissue for bacterial, mycobacterial, and fungal pathogens were negative. Intradermal PPD was negative at a 72-hour

A scleroderma-like cutaneous syndrome associated with a marked Th2-type immune response occurring after a prosthetic joint implant.

A scleroderma-like cutaneous syndrome, occurring after implantation of a prosthetic knee joint in an elderly woman, is reported. This case did not seem to typically fit into any of the known scleroderma-like disorders of the skin described to date. The patient was shown to be sensitized to metals contained in the prosthesis and to mount a Th2-type immune response concomitantly with development of skin fibrosis. In particular, eosinophilia, markedly elevated serum IgE levels, in vitro spontaneous production of interleukin (IL)-4 by T lymphocytes, and elevated serum levels of Th2 cytokines (namely, IL-4, IL-5, and IL-13) were observed during the acute phase of illness. Since eosinophils and such Th2 cytokines as IL-13 also have recognized fibrogenic properties, it is speculated that the pathogenesis of skin fibrosis in this case could have been the direct and/or indirect consequence of the coexisting Th2-type immune response.