Increased cholinergic activity under conditions of low estrogen leads to adverse cardiac remodeling

Cholinesterase inhibitors are used in postmenopausal women for the treatment of neurodegenerative diseases. Despite their widespread use in the clinical practice, little is known about the impact of augmented cholinergic signaling on cardiac function under reduced estrogen conditions. To address this gap, we subjected a genetically engineered murine model of systemic vesicular acetylcholine transporter overexpression (Chat-ChR2) to ovariectomy and evaluated cardiac parameters. Left-ventricular function was similar between Chat-ChR2 and wild-type (WT) mice. Following ovariectomy, WT mice showed signs of cardiac hypertrophy. Conversely, ovariectomized (OVX) Chat-ChR2 mice evolved to cardiac dilation and failure. Transcript levels for cardiac stress markers atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) were similarly upregulated in WT/OVX and Chat-ChR2/OVX mice. 17β-Estradiol (E2) treatment normalized cardiac parameters in Chat-ChR2/OVX to the Chat-ChR2/SHAM levels, providing a link between E2 status and the aggravated cardiac response in this model. To investigate the cellular basis underlying the cardiac alterations, ventricular myocytes were isolated and their cellular area and contractility were assessed. Myocytes from WT/OVX mice were wider than WT/SHAM, an indicative of concentric hypertrophy, but their fractional shortening was similar. Conversely, Chat-ChR2/OVX myocytes were elongated and presented contractile dysfunction. E2 treatment again prevented the structural and functional changes in Chat-ChR2/OVX myocytes. We conclude that hypercholinergic mice under reduced estrogen conditions do not develop concentric hypertrophy, a critical compensatory adaptation, evolving toward cardiac dilation and failure. This study emphasizes the importance of understanding the consequences of cholinesterase inhibition, used clinically to treat dementia, for cardiac function in postmenopausal women.

Neonatal cardiomyocyte hypertrophy induced by endothelin-1 is blocked by estradiol acting on GPER

Estradiol (E₂) prevents cardiac hypertrophy, and these protective actions are mediated by estrogen receptor (ER)α and ERβ. The G protein-coupled estrogen receptor (GPER) mediates many estrogenic effects, and its activation in the heart has been observed in ischemia and reperfusion injury or hypertension models; however, the underlying mechanisms need to be fully elucidated. Herein, we investigated whether the protective effect of E₂ against cardiomyocyte hypertrophy induced by endothelin-1 (ET-1) is mediated by GPER and the signaling pathways involved. Isolated neonatal female rat cardiomyocytes were treated with ET-1 (100 nmol/l) for 48 h in the presence or absence of E₂ (10 nmol/l) or GPER agonist G-1 (10 nmol/l) and GPER antagonist G-15 (10 nmol/l). ET-1 increased the surface area of cardiomyocytes, and this was associated with increased expression of atrial and brain natriuretic peptides. Additionally, ET-1 increased the phosphorylation of extracellular signal-related protein kinases-1/2 (ERK1/2). Notably, E₂ or G-1 abolished the hypertrophic actions of ET-1, and that was reversed by G-15. Likewise, E₂ reversed the ET-1-mediated increase of ERK1/2 phosphorylation as well as the decrease of phosphorylated Akt and its upstream activator 3-phosphoinositide-dependent protein kinase-1 (PDK1). These effects were inhibited by G-15, indicating that they are GPER dependent. Confirming the participation of GPER, siRNA silencing of GPER inhibited the antihypertrophic effect of E₂. In conclusion, E₂ plays a key role in antagonizing ET-1-induced hypertrophy in cultured neonatal cardiomyocytes through GPER signaling by a mechanism involving activation of the PDK1 pathway, which would prevent the increase of ERK1/2 activity and consequently the development of hypertrophy.

Abstract 086: The Angiotensin-(1-7) Mas Receptor Protects Heart and Lung Against Lps-induced Shock in Mice

The renin-angiotensin system (RAS) plays a key role inthe modulation of multiple functions in many organs. It has been demonstrated that the protective axis Ang-(1-7)/ACE2/Mas exerts anti-inflammatory effects in different disorders. Along this line, we have shown that Mas receptor deficiency exacerbates lipopolysaccharide(LPS)-induced cerebral and systemic inflammation in mice. In this study, we investigate the effects of LPS-induced shock in a mouse model for global increases in Mas receptor expression (UB8 mice). Mice were injected intraperitoneally (i.p.) with LPS, and experiments were performed 1h (RT-qPCR and ELISA) and 6 h (Echocardiography, NAG activity, and Lung histological analysis) after injection (except for the survival curve experiment). Cytokine gene expression was significantly attenuated in the left ventricle (LV) of UB8 vs. FVBN mice (p<0.05) the 1 hour after LPS (5mg/kg) administration: IL6 (119.7 ± 26.9 vs.199.6 ± 31.9 a.u), TNFα (59.3 ± 5.8 vs.89.2 ± 5.9 a.u), IL1β(56.6 ± 11,5 vs.122.8 ± 20.4 a.u) and IL10 (33.8 ± 3.5 vs.72.6 ± 5.8 a.u). Similar results were observed in serum protein levels: IL6 (6,651 ± 946.4 vs.3,203 ± 904.1 pg/ml), TNFα (925.5 ± 56.6 vs. 1,380 ± 114.1 pg/ml), IL1β (2,844 ± 462.2 vs. 5,876 ± 841.5 pg/ml) and IL10 (8.8 ± 6.4 vs.230.6 ± 54.4 pg/ml). In FVBN mice, LPS (15 mg/kg) significantly decreased stroke volume (before: 31.92 ± 2.44 after LPS: 17.50 ± 1.61 ul), cardiac output (before: 30.92 ± 2.35 after LPS: 16.83 ± 1.56 ml/min) but in the LPS-treated UB8 mice, no changes were observed in cardiac function. Additionally, Increases in NAG activity in the LV and lung and in Alveolar Wall Thickening (AWT) were seen only in FVBN mice after LPS administration (LV NAG FVBN sham vs. FVBN LPS: 0.051 ± 0.008 vs. 0.096 ± 0.004 U/L and lung: 0.030 ± 0.034 vs. 0.673 ± 0.093; AWT FVBN sham: 0.794 ± 0.160 vs FVBN LPS 1.781 ± 0.118 m2). Finally, we found a significant increase in survival of UB8 mice (60.32 %) vs. FVBN (48.3%) after LPS administration (30mg/kg). Taken together, these results indicate that global increase in receptor Mas expression in mice exerts protective actions in heart and lung against LPS challenge, highlighting the therapeutic potential of Mas axis during inflammatory processes.

Abstract P140: Alamandine Signaling in Cardiomyocytes in Health and Disease

Alamandine is a new component of the renin-angiotesin system generated from angiotensin A or angiotensin-(1[[Unable to Display Character: &#8211;]]7). Its biological actions include vasodilation, and antihypertensive effects. In the heart, the molecular pathways activated by alamandine have not been characterized. Our goal was to investigate the signaling pathways activated by alamandine in ventricular myocytes isolated from both healthy and hypertensive models. Cardiomyocytes isolated from C57BL/6 mice and from rats that overexpress renin (TGRmRen) were treated with 100nmol/L alamandine. Intracellular nitric oxide (NO) and Ca 2+ levels were recorded in cells loaded with DAF-FM and Fluo4-AM, respectively. Protein phosphorylation was assessed by western-blot. In cardiomyocytes, alamandine induced an increase in phosphorylation of PDK1 (arbitrary units (a.u.): control=0,20±0.06 versus alamandine=0,42±0.08 n=6, p<0.05) and Akt Ser473 (a.u.: control= 0,40 ±0,01 versus alamandine= 0,52±0,10 n=5 p<0.05). Moreover, alamandine induced a significant increase in NO (Fluorescence a.u.: control=4.8±0.8 n=44 versus alamandine=12.19±1.47 n=85 p<0.05), without any effect on Ca 2+ transient amplitude. Ventricular myocytes treated with alamandine showed decreased GSK3β phosphorylation (a.u.: control=0,62±0.19 versus alamandine=0,50±0.25 n=5 p<0.05) and increased phosphorylation of ERK1/2 (a.u.: control=0,48±0.24 versus alamandine= 0,80±0.29, n=7 p<0.05) when compared to control. Conversely, TGRmRen cardiomyocytes exposed to alamandine showed increased GSK3β phosphorylation and decreased phosphorylation of ERK1/2. The effect of alamandine on Akt phosphorylation was preserved in TGRmRen cardiomyocytes. Furthermore, alamandine treatment prevented both cardiomyocyte hypertrophy (area (μm 2 ): control=447±23 n=58; angiotensin II= 609±26 n=70; angiotensin II+alamandine= 491±31 n=45 p<0.05), and nuclear translocation of GRK5 induced by 100nmol/L angiotensin II. Our data show that alamandine signaling in cardiomyocytes changes according to different pathophysiological condition, and includes the activation of cardioprotective pathways. These data highlight the therapeutic potential of alamandine in the heart.

Increased reperfusion by glycoprotein IIb/IIIa receptor antagonist administration in case of unsuccessful and failed thrombolysis in patients with acute myocardial infarction: a pilot study

BACKGROUND

The aim of this study was to evaluate the effectiveness of glycoprotein (GP) IIb/IIIa receptor inhibitors in acute myocardial infarction (AMI) patients in case of unsuccessful and failed thrombolysis.

METHODS

Eighty-four patients hospitalized within 4 hours of symptom onset were randomized (single blind) into two groups. Regardless of the group, placebo or GP IIb/IIIa inhibitors were administered to patients who did not present with reperfusion signs (failed thrombolysis) 30 min after starting thrombolysis and 30-60 min after the end of full thrombolysis in patients with pain recurrence and ST-segment elevation (unsuccessful thrombolysis). Reperfusion was assessed by the creatine kinase peak occurring within 12 hours, by the observation of rapid ST-segment reduction (50-70% within 1 hour) in the 12-lead ECG continuous tracing, by the rapid regression of pain and by the development of early ventricular arrhythmias. Group 1 patients (n = 42) received, during failed thrombolysis or after 30-60 min of effective thrombolysis but with pain recurrence and ST-segment elevation (unsuccessful thrombolysis), treatment with i.v. GP IIb/IIIa inhibitors, heparin according to the TIMI 14 trial, and aspirin. Group 2 patients (n = 42) received a full dose of recombinant tissue-type plasminogen activator (rt-PA 100 mg) and placebo either during failed thrombolysis or, after 30 min of effective thrombolysis but with pain recurrence and ST-segment elevation, and standard heparin treatment and aspirin.

RESULTS

In group 1, 39 patients showed rapid reperfusion (4 +/- 3 min); 22 patients received rt-PA 65 mg and 20 patients received rt-PA 100 mg and subsequent GP IIb/IIIa inhibitor treatment. Coronary angiography, performed after 12-72 hours showed patency of the infarct-related artery in 39 patients whose clinical picture was suggestive of rapid reperfusion during administration of a bolus of GP IIb/IIIa inhibitors. In group 2, no patients showed reperfusion and they were submitted to rescue coronary angioplasty (p < 0.05). Side effects occurred in 3 cases in group 1 and in 2 cases in group 2. Patients receiving GP IIb/IIIa inhibitors showed a reduced incidence of stent treatment (p = NS) and a significant reduction in the occurrence of events (angina) within 30 days of treatment (p = NS).

CONCLUSIONS

Our data suggest that in patients with AMI and failed thrombolysis, treatment with GP IIb/IIIa receptor inhibitors is feasible. The increase in the risk of bleeding was acceptable. The most important result was that this combination is safe.

ACE-inhibition plus mineralocorticoid antagonism versus ACE-inhibition alone in patients with anterior myocardial infarction

BACKGROUND

Aldosterone exerts pro-fibrotic effects, acting via mineralo-corticoid reeptors in cardiovascular tissues. Aldosterone antagonism in combination with ACE inhibition may better protect against untoward effects of aldosterone than ACE inhibition alone.

METHODS

In a double blind, randomised study the tolerability and efficacy of canreonate (25 mg/day) plus captopril versus captopril alone were evaluated in 187 patients with an acute anterior myocardial infarction (MI) and a serum creatinine concentration <2.0 mg/dL and a serum K concentration <5.0 mmol/L. Ninety-four patients received captopril and 25 mg canreonate (group A). Group B (93 patients) received captopril and placebo. At baseline and at 10 and 90 days after admission Doppler echocardiography was performed.

RESULTS

Clinical and demographic aspects were similar in both groups. Also, baseline cardiac enzyme levels, left ventricular (LV) function and incidence of surgical interventions and angioplasty were comparable. Overall, creatinine, blood urea and serum K did not show significant differences between groups. However, in 9 patients in group A increases in serum K >5.5 mmol/dL and creatinine >2.0 mg/L were observed after 10 days of treatment. At 90 days, the mitral E/A ratio was higher (p = 0.001) and LV end systolic volume smaller (p = 0.021) inpatients treated with canreonate than in those receiving placebo. No further side effects were observed during the study period.

CONCLUSIONS

Our data suggest that the combination of captopril plus canreonate is well tolerated following an acute myocardial infarction and has a beneficial effect on diastolic and systolic LV parameters and may decrease post-MI remodelling.

The combination ace-inhibitors plus canreonate in patients with anterior myocardial infarction: safety and tolerability study

BACKGROUND

There is recent evidence that aldosterone (ALDO) exerts pro-fibrotic effects, acting via the mineral-corticoid receptors in cardiovascular tissues and partial aldosterone escape during ACE-inhibition treatment occurs.

METHODS

A double blind randomised study was performed to evaluate the feasibility, and tolerability of the administration of the 25 mg/day of canreonate plus captopril versus captopril alone in patients with anterior AMI unsuitable for thrombolysis and/or not receiving thrombolytic treatment, and unreperfused after thrombolysis. Fifty five patients hospitalised for anterior AMI,with a serum creatinine concentration <2.0 mg/dl and a serum K concentration <5.0 mmol per liter were randomised in 2 groups: Group A included 27 patients who received captopril and 25 mg i.v. of canreonate (1 mg/h for the 1st 72 h and then orally 25 mg/day. Group B (28 patients) received captopril and placebo. Ten days after admission they underwent echocardiography to determine end systolic volume (ESV), ejection fraction (EF), End diastolic diameter EDD, E/A ratio, E deceleration time (dec. time) and isovolumetric relaxation time (IVRT), E and A peak velocities.

RESULTS

All patients did not show patency of the infarct related artery (7-10 days after AMI) and the 2 groups were similar in regard to age, sex, diabetes, smoking habits, hypertension, CK enzymatic peak, adjuvant therapy, EF, ESV, and incidence of CABG/PTCA. One patient only showed increase of serum K>5.5 mmol/dl and creatinine >2.0 mg per liter after 10 days of treatment (group A). The mitral E/A ratio was higher in group A than group B (0.85+/-0.18 and 0.75+/-0.14) respectively, P=0.024. Creatinine, blood urea and serum K did not show significant differences between groups. No side effects were observed during the study period. The incidence of vessel diseases was similar in both groups.

CONCLUSIONS

Our data suggest that the combination of captopril plus canreonate in feasible in early treatment of AMI patients.

Effects of trimetazidine administration before thrombolysis in patients with anterior myocardial infarction: short-term and long-term results

Reperfusion may prevent or reduce the development and extent of necrosis, but may also lead to an increase in reperfusion damage. Experimental studies performed in various animal models of myocardial ischemia have demonstrated the anti-ischemic properties of trimetazidine (TMZ) and have suggested that TMZ has antioxidant properties, without any direct hemodynamic effects. Our study was aimed at investigating the effects of TMZ before thrombolysis in acute anterior myocardial infarction and included 81 patients, hospitalized within 4 hours of the onset of symptoms. Patients were randomly (double-blind) subdivided in two groups The first group (40 patients, Group A, TMZ-pretreatment), received 40 mg TMZ orally about 15 minute before thrombolysis and, subsequently, 20 mg every 8 hours. The second group (41 patients, Group B) received placebo before thrombolysis. Ventricular arrhythmias (VA) due to reperfusion were evaluated in the first 2 hours. VA occurred in 15 of patients in group A, versus 29 in group B, p<0.05. Creatine kinase (CK) normalization time was achieved after 55.7+/-12.5 hours in group A, versus 61.2+/-12.1 hour in group B, p = 0.048. CK peak was 1772+/-890 in group A vs. 2285+/-910 Ul/l in group B, (p = 0.012). In the follow-up (range 6-22 months), there were 4 deaths, two patients in each group. After 180 days from treatment, the TMZ group showed a smaller end systolic volume than the placebo group (echocardiographic data), 46.2+/-12 and 52.8+/-13 ml/m2, respectively, p = 0.037. Our data suggest that TMZ probably reduces reperfusion damage and/or infarct size in patients with anterior AMI subjected to thrombolysis and affects the post-AMI remodeling. Our data must be interpreted with caution because of the selection of patients. These findings require further extensive trials.

Does the addition of losartan improve the beneficial effects of ACE inhibitors in patients with anterior myocardial infarction? A pilot study

OBJECTIVE

To verify the efficacy of the combination of captopril (75 mg day) and losartan (25 mg/day) in early postinfarction phases of reperfused anterior acute myocardial infarction.

DESIGN AND PATIENTS

99 patients, hospitalised for suspected anterior acute myocardial infarction within four hours from the onset of symptoms, were randomised into two groups: group A included 50 patients who received captopril 75 mg/day and placebo; group B included 49 patients who received captopril 75 mg/day within three days of admission plus losartan 12.5 mg, as a first dose, and 25 mg/day successively. An additional 23 patients with anterior acute myocardial infarction received losartan 25 mg alone and acted as controls (group C) to check the effects of losartan on plasma angiotensin II (AII) concentrations. Noradrenaline (norepinephrine) (NA) and AII plasma concentrations were measured on the third and 10th day after admission in 93 patients (35 from group A, 35 from group B, and 23 from group C). 90 days after admission patients underwent echocardiography to determine end systolic volume (ESV) and ejection fraction (EF).

RESULTS

Patients in groups A and B were similar with regard to age, sex, creatine kinase peak, EF, ESV, and risk factors. Group B (captopril plus losartan) patients showed a significant reduction in mean (SD) systolic blood pressure within the group (basal 128 (10) mm Hg; 10 days after admission 105 (9) mm Hg, p < 0.001), and in comparison with group A (captopril) patients (basal 127 (11) mm Hg; 10 days after admission 116 (10) mm Hg, p < 0. 001). Diastolic blood pressure was also lower in group B patients versus group A (66 (11) v 77 (11) mm Hg). Group C (losartan) patients also showed a significant reduction in systolic blood pressure (131 (13) mm Hg down to 121 (12) mm Hg, p < 0.001). Neither NA nor AII plasma concentrations in groups A and B differed significantly in basal samples (NA 673 (138) v 675 (141) pg/ml; AII 12.77 (4.79) v 12.65 (4.71) pg/ml) or 10 days after admission (NA 283 (93) v 277 (98) pg/ml; AII 5.31 (2.25) v 6.09 (3.31) pg/ml). However, patients in group C had higher plasma concentrations of AII (14.79 (5.7) pg/ml on the third day and 7.98 (4.92) pg/ml on the 10th day) than patients in either group A or B (p = 0.006). After 90 days following treatment, group B (captopril plus losartan) patients had a smaller ESV than patients in group A (captopril) and group C (losartan).

CONCLUSION

The data suggest that the combination of captopril plus losartan is feasible in the early treatment of acute myocardial infarction patients, and it appears that this combination has more effect on ESV than captopril alone in the short term.

Safety, tolerability, and neurohormonal changes of the combination captopril plus losartan in the early postinfarction period: a pilot study

Suppression of formation of angiotensin II (A-II) is thought to be a major contributor to the hemodynamic response to angiotensin-converting enzyme inhibition (ACE-in) therapy. However, angiotensin II (A-II) plasma levels may rebound during ACE-in treatment. The study sought to verify the feasibility, safety, and tolerability of the combination of captopril (75 mg/d) plus losartan (25 mg/d). We also wished to establish whether the combination was able to avoid the increase of angiotensin II resulting from losartan treatment in early postinfarction phases of reperfused anterior acute myocardial infarction (AMI). Forty-four patients, hospitalized for suspected anterior AMI within 4 hours from the onset of symptoms, suitable for thrombolysis (first episode), Killip class I-II and reperfused, receiving 75 mg/d of captopril within 3 days from admission, and with systolic blood pressure (BP) >120 mmHg were randomized (single-blind) into two groups: Group A included 22 patients (6 women and 16 men) and received captopril 75 mg/d and placebo. Group B included 22 patients (5 women and 17 men) and received captopril 75 mg/d within 3 days from admission plus losartan 12.5 mg, as the first dose, and 25 mg/d (BP >110 mmHg) successively. Norepinephrine (NE) and A-II levels were measured on the 3rd and 10th days after admission. The two groups were similar with regard to age, sex, creatinine kinase peak, ejection fraction, end-systolic volume, and risk factors. Group B (captopril plus losartan) showed a significant reduction of BP, from 124 +/- 8.5 mmHg to 108 +/- 6.4 mmHg, P < 0.001, at 10 days after admission. In group A, BP was 122 +/- 9 mmHg, and 10 days after admission BP was 118 +/- 11 mmHg. NE and A-II values did not show significant differences in basal samples. At 10 days after admission values were NE 298 +/- 90 versus 272 +/- 86 pg/mL and A-II 6.07 +/- 2.97 versus 5.29 +/- 2.05 pg/mL for the two groups. Our data suggest, for the first time, that the combination of captopril plus losartan is feasible and does not produce serious side effects. When losartan was added to ACE-in treatment, there was no significant increase in A-II.

Early captopril treatment reduces plasma endothelin concentrations in the acute and subacute phases of myocardial infarction: a pilot study

It has been reported that endothelin-1 (ET-1) increases in acute myocardial infarction (AMI). Experimental studies showed that captopril administration reduces ET-1 secretion. In addition, it was reported that the increased ET-1 levels are a negative prognostic index. The study sought to verify whether captopril can reduce plasma ET levels in the acute and subacute phases of reperfused anterior AMI. Forty-five patients, hospitalized for suspected anterior AMI within 4 h from the onset of symptoms, suitable for thrombolysis (first episode), Killip class I-2, were randomized (double blind) into two groups: group A (23; seven women/16 men) received captopril (as first dose) 2-4 h after starting thrombolysis (the dose was then increased up to 25 mg every 8 h). Group B (22; five women/17 men) received placebo after thrombolysis. All the patients met the reperfusion criteria. The two groups were similar with regard to age, sex, CK peak, ejection fraction, end-systolic volume and risk factors. Plasma ET levels were measured at entry, and 2, 12, 24, 48, and 72 h after starting thrombolysis. Mean concentrations of ET +/- SD: Group A basal, 1.50 +/- 0.67; at 2h, 2.31 +/- 1.24; 12 h, 1.84 +/- 1.45; 24 h, 1.30 +/- 0.72; 48 h, o.95 +/- 0.50; 72 h, 0.60 +/- 0.15 fmol/ml; p < 0.001. Group B basal, 1.58 +/- 0.83; at 2 h, 2.38 +/- 1.35; 12 h, 2.33 +/- 1.71; 24 h, 1.80 +/- 1.41; 48h, 1.46 +/- 0.88; 72 h, 0.93 +/- 0.44 fmol/ml; p < 0.001. Difference between the two groups was significant at the beginning of the test (between 2 and 12 h, p[=]0.002). After that, the values of the plasma endothelin decreased in parallel, p < 0.001. Our data suggest that captopril affects plasma ET levels in the acute and subacute phases of AMI. Moreover, these results provide additional evidence for a beneficial effect of early captopril treatment.

Immunological and functional comparison between Clostridium perfringens iota toxin, C. spiroforme toxin, and anthrax toxins

Clostridium perfringens iota and C. spiroforme toxins consist of two separate proteins. One is the binding component and the other the enzymatic component. The two toxins secreted by Bacillus anthracis are composed of binary combinations of three proteins: protective antigen, lethal factor, and edema factor. As shown by Western blotting and ELISA, the binding component of anthrax toxin shares common epitopes with that of iota toxin and C. spiroforme toxin which are closely related immunologically. However, no functional complementation was observed between iota toxin and anthrax toxin components. The binding components can form toxins active on macrophages only in combination with their respective enzymatic components. Agents which prevent acidification of endosomes do not have the same effects on anthrax toxin activity as they do on iota and C. spiroforme toxins. Therefore, the mechanisms of entry into the cells are presumably different. Since the binding components of anthrax toxins and iota toxin share a conserved putative translocation domain, these binding components could have a common mode of insertion into the cell membranes.

[Is the reduction of the plasma levels of endothelin in the acute and sub-acute stage of myocardial infarct one of the beneficial effects of early treatment with ace inhibitors?]

BACKGROUND

Studies showed that endothelin-1 (ET-1) was increased in the acute myocardial infarction (AMI). Experimental studies reported that captopril was able to reduce ET-1 secretion. In addition increased levels of ET-1 were reported as a negative prognostic index. The study was aimed to verify whether captopril was able to reduce plasma ET-1 levels in the acute and subacute phases of AMI.

METHODS

Forty five patients, hospitalized for suspected anterior AMI within 4 h since the onset of symptoms, suitable for thrombolysis (first episode), in Killip class 1-2, were randomized (double blind) into two groups: Group A (23 patients, pts), 7 females and 16 males, received captopril 6.25 mg orally (as first dose) 2-4 h after starting thrombolysis, and the doses of captopril were successively increased up to 25 mg every 8 h. Group B: (22 pts), 5 females and 17 males, received placebo after thrombolysis. All the patients met the reperfusion criteria.

RESULTS

The two groups were similar for age, sex, CK peak, ejection fraction, end systolic volume and risk factors. Plasma ET levels were checked on admission, and 2, 12, 24, 48, 72 hours, after starting thrombolysis. Mean concentrations of ET +/- SD: Group A: basal 1.50 +/- 0.67, at 2 h 2.31 +/- 1.24, 12 h 1.84 +/- 1.45, 24 h 1.30 +/- 0.72, 48 h 0.95 +/- 0.50, 72 h 0.60 +/- 0.15 fmol/ml (p < 0.001). Group B: basal 1.58 +/- 0.83, at 2 h 2.38 +/- 1.35, 12 h 2.33 +/- 1.71, 24 h 1.80 +/- 1.41, 48 h 1.46 +/- 0.88, 72 h 0.93 +/- 0.44 fmol/ml (p < 0.001). Difference between the two groups was significant at 48 h (p < 0.05), and 72 h (p < 0.001).

CONCLUSIONS

Our data suggest that captopril affects plasma endothelin levels in the acute and subacute phases of AMI. In addition, our results seem to be an additional support to the beneficial effects of early captopril treatment in patients with AMI.

Captopril does not affect plasma endothelin-1 during thrombolysis and reperfusion

Studies showed that endothelin-1 (ET-1) was increased in the acute myocardial infarction (AMI). Experimental studies reported that captopril was able to reduce ET-1 secretion, and that ET-1 was increased during reperfusion. This study was aimed to verify if captopril was able to reduce plasma ET-1 during thrombolysis in AMI. Seventy-three patients, hospitalized for suspected AMI within 4 h from the onset of symptoms suitable for thrombolysis (1st episode), Killip class 1-2, were randomized (double blind) into two groups: group 1 (37 pts), 8 F/29 M, received captopril, 6.25 mg, orally 15 min before thrombolysis. Group 2: (36 pts) 8 F/28 M, received placebo before thrombolysis. All patients met the reperfusion criteria. Plasma ET-1 were checked on admission, at 1 h and at 2 h, after starting thrombolysis. Group 1 contained ten unstable angina, 17 anterior and ten inferior AMIs. Group 2 contained ten unstable angina, 16 anterior and ten inferior AMIs. Mean concentrations of ET-1: Unstable angina: group 1, basal--4.56, at 1 h--4.47, 2 h--5.89 pg/ml; group 2: basal--4.17, at 1 h--4.59, 2 h--5.24 pg/ml. Inferior AMI: group 1: basal--6.87, 1 h--7.75, 2 h--8.47; group 2: basal--6.34, 1 h--6.68, 2 h--7.98 pg/ml. Anterior AMI: group 1: basal--7.17, 1 h--7.93, 2 h--10.76 pg/ml (between basal and 2-h samples P < 0.05); group 2: basal--7.46, 1 h--7.51, 2 h--10.74 pg/ml. Differences between the two groups were not significant. Our data suggest that captopril does not affect plasma ET-1 during thrombolysis.

Advantages of immediate two-dimensional echocardiography in patients with acute cardiac ischemic events

We hypothesized that the assessment of kinetic alterations on two dimensional echocardiogram (2DE) would provide greater diagnostic information than clinical symptoms and ECG changes only. The study was aimed to determine sensitivity of 2DE in patients with cardiac ischemic events and to improve the indications to thrombolysis. Three-hundred ninety-one patients (87 F; 304 M) hospitalized for suspected acute myocardial infarction (AMI), first episode, within 4 h from the onset of symptoms, suitable for thrombolysis Killip class I-II and with unstable angina (UA), were admitted in the study. Patients had to show ECG changes and alterations of segmentary motion on 2DE performed at entry, or 2DE alterations without ECG changes. The 2DE variables analyzed included right ventricular function and left ventricular systolic function. Thrombolysis was performed when 2DE and ECG changes were evidenced at the same time and when 2DE alterations without ECG changes were observed. Patients with UA treated with heparin alone were also studied. The presence of segmentary motion alterations was mandatory.

RESULTS

Inferior AMIs, 87 patients (60 +/- 13 years), anterior AMI, 169 patients (61 +/- 11 years); UA group subjected to thrombolysis, 87 patients (62 +/- 12 years); UA group treated with heparin, 48 patients (62 +/- 12 years). We noted only one patient false negative, and five patients false positive. Alterations of right ventricular function were observed in 24, 14 and nine patients with inferior, anterior AMI and UA, respectively. Normal ECG at entry was observed in seven, two and seven patients with inferior, anterior AMI and UA, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Intracellular heme coordinately modulates globin chain synthesis, transferrin receptor number, and ferritin content in differentiating Friend erythroleukemia cells

The effect of succinylacetone (SA), a highly specific inhibitor of ALA-dehydratase and heme synthesis, on hemoglobin (Hb) production, transferrin receptor (TfR), and ferritin expression was analyzed in differentiating Friend leukemia cells (FLC). This compound exerted a pronounced inhibitory effect not only on heme and Hb synthesis, but also on all the remaining above-mentioned parameters. In particular, SA induced: (1) a reduction of the level of alpha-globin mRNA; (2) a decreased number of exposed TfR molecules, without modification of their affinity for the ligand; (3) a reduced level of TfR RNA, without significant change of TfR gene transcription rate; and (4) a lower ferritin content. The addition of exogenous hemin to differentiating FLC exerted opposite effects, and particularly induced an increase of both the number of TfRs and ferritin content. These findings suggest that in erythroid cells optimal heme synthesis is required to coordinately sustain globin chains synthesis and TfR/ferritin production; thus, the intracellular heme level may represent a key regulatory factor in the Hb synthesis pathway.

IL-6/BSF-2 selectively stimulates the GO----S progression of CD8+ lymphocytes

IL-6 preferentially promotes the DNA synthesis of human peripheral blood CD8+, rather than CD4+, lymphocytes in presence of PHA: this effect is observed in serum-free cultures of greater than 99% purified CD8+ lymphocytes. However, IL-6 is able to stimulate DNA synthesis of CD8+ lymphocytes triggered by a mitogenic anti-CD2 mAb, but not by anti-CD3 mAb: these results suggest that IL-6 selectively induces activation of CD8+ lymphocytes through the CD2 rather than the CD3 pathway. Limiting dilution analysis indicates that accessory cells are not required to mediate the action of IL-6 on CD8+ cells. Furthermore, this action is not blocked by addition of mAb neutralizing either IL-2 or IL2R, thus suggesting that IL-6 does not act via IL-2. CD8+ lymphocytes grown in the presence of PHA + IL-6 incorporate (3H)-thymidine to the same extent as those stimulated with PHA + IL-2, but do not increase in number until day 6 of culture. It is hence apparent that the stimulating activity of IL-6 on CD8+ lymphocytes is restricted to the GO----S phase progression, but does not lead to mitosis. IL-6 receptors are expressed on resting CD4+ and CD8+ lymphocytes: their expression is significantly enhanced on both activated CD4+ and CD8+ cells. Scatchard analysis of (125I)-IL-6 binding data showed the presence of high (Kd, 3 x 10(-10) M) and low (Kd, 6 x 10(-8) M) affinity IL6R on both lymphocyte populations. Similarly, mRNA encoding IL6R was detected in both CD4+ and CD8+ lymphocytes. Thus, our studies indicate that IL-6 directly and selectively stimulates the GO----S progression of CD8+ lymphocytes in the presence of mitogen and absence of IL-2: this phenomenon may be of interest for the elucidation of mechanisms activating cytotoxic T lymphocytes.

Primary hypothyroidism associated with interleukin-2 and interferon alpha-2 therapy of melanoma and renal carcinoma

Four patients out of twenty with renal cancer and melanoma undergoing cancer immunotherapy with interleukin 2 (IL-2) and interferon alpha-2 (IFN-alpha 2) had laboratory evidence of hypothyroidism starting at cycle three to six, with a decline in serum thyroxine below normal and, in three cases, a rise in serum thyrotropin and thyroglobulin. One hypothyroid patient had elevated serum antimicrosomal antibody titres before the start of treatment and two others responded similarly during therapy. Three of the sixteen euthyroid patients also developed elevated titres of this antibody. Partial or complete remission was observed in seven of the patients--three of the four with hypothyroidism showed tumour regression. Thus IL-2 and IFN-alpha 2 can cause hypothyroidism, presumably via induction or exacerbation of autoimmune thyroid reactions. The occurrence of hypothyroidism may be mediated by high-dose IL-2 (rather than by LAK cell therapy as previously suggested) and potentiated by IFN-alpha 2.