Leukocyte/endothelium activation and interactions during femoral percutaneous transluminal angioplasty.

Recent data suggest that leukocyte-endothelium activation/interactions are important for restenosis after percutaneous transluminal angioplasty (PTA). Ten patients with superficial femoral artery occlusive disease (stage Fontaine IIb) were examined after a percutaneous transluminal angioplasty (PTA) versus a preceding aortoangiography (AAG). Blood samples from corresponding femoral arteries and veins were obtained before, immediately after, and 4 hours after each procedure. The authors examined the ex vivo respiratory burst and leukocytic expression of adhesion molecules flowcytometrically, adhesion molecule plasma concentrations, and inflammatory mediators concentrations in plasma and in endotoxin-stimulated whole blood cultures by ELISA, and the leukocyte counts. After PTA, venous plasma concentrations of soluble (s)L-selectin (148.2 +/-14.7%, p<0.05 vs 100% baseline +/- sem), sP-selectin (130.7 +/-6.9%, p<0.01; sE-selectin (117.5 +/-8.3%, p<0.05 vs arterial), sLFA-3 (130.7 +/-15.8%, p<0.05) were increased. Expressions of L-selectin (93.0 +/-5.7%, p<0.05 vs arterial), CD11a (98.8 +/-3.8%, p=0.06), CD18 (96.9 +/-4.0%, p<0.05 vs arterial), and ICAM-1 (89.1 +/-7.7%, p<0.05) on polymorphonuclear neutrophils (PMN), and arteriovenous leukocyte counts (arterial: 103.5 +/-5.4%, venous: 91.1 +/-3.3%, p<0.05) decreased. Venous ex vivo secretions of oxygen radicals (141.4 +/-28.1%, p<0.05 vs AAG), PMN-elastase (173.7 +/-35.7%, p<0.05 vs AAG), and interleukin (IL)-8 (226.5 +/-56.4%, p<0.001; p<0.0001 vs AAG), as well as PMN-elastase (173.7 +/-35.7%, p<0.05 vs AAG) and tumor necrosis factor (TNF)-alpha plasma concentrations (124.1 +/-11.9%, p=0.06) rose. Four hours after PTA, a leukocytosis and exhausted TNF-alpha (69.8 +/-10.4%, p<0.05) and IL-8 secretions (72.4 +/-4.6%, p<0.01) occurred. PTA induced local leukocyte-endothelium activations (stronger ex vivo mediator productions) and interactions (decreased venous leukocyte counts, increased plasma concentrations, and decreased leukocytic expression of adhesion molecules) with the release of inflammatory mediators (higher plasma concentrations and exhaustions after 4 hours).

[Pharmacotherapy of severe heart failure with inodilators--new approaches]. / Pharmakotherapie der schweren Herzinsuffizienz mit Inodilatoren--Neue Ansätze.

Severe congestive heart failure and cardiogenic shock don't resemble a homogeneous clinical picture, but a syndrome that is based on very different etiologies. What all the etiologies have in common is the inadequate peripheral O2-supply to essential organs with or without signs of severe pulmonary congestion up to pulmonary edema. For prognosis and therapy is a fast diagnostical clarification of the causes crucial. The therapeutical procedure for the various etiologies may be diametrically opposed. For the therapy is it also dicisive to distinguish between acute myocardial failure, e.g. acute myocardial infarction, and the development of myocardial failure from a longer existing consistent congestive heart failure (cardiomyopathy). Whenever possible, next to symptomatically therapy of cardiogenic shock the basic conditions of the disease should be cured (e.g., PTCA, lysis with acute myocardial infarction, lysis in acute pulmonary embolism). In myogenic cardiogenic shock the use of positive-inotropic substances with and without simultaneous vasodilatory effects, if necessary in combination with other vasodilators, may be life-saving. Up until now there still doesn't exist an alternative to the catecholamines in the acute phase, initially they should be used as a first-line-therapy to stabilize the hemodynamics. The insertion of a Swan-Ganz-catheter for invasive therapy-monitoring, especially for the regulation of the therapy is a "condition sine qua non" for every patient with unstable hemodynamics. Because of the prompt beta-receptor-down-regulation during shock, caused by endogenous catecholamines, successful therapy with exogenous catecholamines is limited (adrenaline, dopamine, dobutamine), on account of the acceleration and intensification of the beta-receptor-down-regulation process. Possible beta-receptor independent alternatives are beta 2-agonists (dopexamine), PDE-III-inhibitors (amrinone, milrinone, enoximone) as well as H2-receptor agonists (impromidine, arpromidine) and finally the calcium-sensitisers (pimobendane). First results give rise to optimism to effectively reduce the mortality of congestive heart failure. The combination of these new pharmacological possibilities with interventional transcutaneous applicable assist-systems (aortic counterpulsationpump IABP, hemopump, transcutaneous heart-lung-machine) as well as the transitory application of an artificial heart (Novacor) can possibly increase the success of these therapeutic strategies. So far there are no convincing results shown in the world literature.

The role of vasopressin in the nicotine-induced stimulation of ACTH and cortisol in men.

Experimental evidence indicates that arginine vasopressin (AVP) contributes to the release of ACTH under certain conditions. The present study investigates the role of vasopressin as a secretagogue of ACTH during cigarette smoking or nicotine infusion with additional injection of corticotropin releasing hormone (CRH) and using the specific AVP antagonist d(CH2)5Tyr(Me)-AVP. We first tested the effect of the AVP antagonist (10 micrograms/kg body weight i.v.) on ACTH and cortisol release following cigarette smoking in 15 healthy young male smokers. Smoking led to marked increments in plasma nicotine and to a small rise in plasma ACTH and cortisol. Mean plasma ACTH and cortisol levels were at no time significantly altered by the antagonist. This might be due to a slight agonistic effect of the AVP antagonist, to high interindividual variability of the ACTH and cortisol responses after smoking or to a negligible role of AVP in smoking-induced ACTH release. In a second study we performed the following tests in six healthy male non-smokers: (1) nicotine infusion (1.0 micrograms/kg body weight per min); (2) CRH i.v. (100 micrograms); (3) AVP antagonist i.v. (5 micrograms/kg); (4) nicotine infusion plus CRH i.v.; (5) nicotine infusion plus AVP antagonist i.v.; (6) nicotine infusion plus CRH and AVP antagonist i.v.; and (7) sham infusion. Nicotine infusion led to greater increments of AVP, ACTH and cortisol than smoking without causing nausea. Peak nicotine levels after nicotine infusion were lower than after smoking. The AVP antagonist in the reduced dosage given alone had no effect on hormone levels. However, it slightly attenuated the effect of nicotine on ACTH and cortisol (P less than 0.05, ANOVA).(ABSTRACT TRUNCATED AT 250 WORDS)

Stimulation of steroid secretion by adrenocorticotropin injections and by arginine vasopressin infusions: no evidence for a direct stimulation of the human adrenal by arginine vasopressin.

Arginine vasopressin stimulates the secretion of adrenocorticotropin. A direct stimulatory effect of AVP on cortisol as well as aldosterone secretion has been postulated by several investigators. To study the possible role of a direct stimulatory action of AVP on the adrenal cortex, normal volunteers were treated with incremental injections of ACTH or with incremental infusions of AVP which raised plasma AVP levels to a maximum of 256 +/- 16 pmol/l. In both situations, a significant (p less than 0.001) linear correlation between plasma ACTH and plasma cortisol was observed. The regression coefficients were not different (p greater than 0.5). Plasma aldosterone was stimulated by both treatments, but the weakly positive correlation between plasma ACTH and plasma aldosterone was not significant for either stimulus. Thus, in man, a direct stimulatory effect of AVP on cortisol secretion cannot be demonstrated. A direct effect of AVP on aldosterone cannot be definitely excluded, but is certainly of minor importance.

Effects of a V1-vasopressin antagonist on ACTH release following vasopressin infusion or insulin-induced hypoglycemia in normal men.

Experimental evidence indicates that arginine vasopressin contributes to the release of adrenocorticotropic hormone under certain conditions. We studied for the first time the AVP antagonist [d(CH2)5 Tyr(Me)AVP] in 6 normal men in order to evaluate the possible role of AVP as an ACTH-releasing hormone during insulin-induced hypoglycemia. To test the agent's capacity to inhibit an ACTH release by exogenous AVP, we compared the ACTH response to an infusion of 300 ng AVP/min a. 30 min after injection of 5 micrograms/kg of the antagonist, b. after injection of placebo (0.9% NaCl). Plasma ACTH levels during AVP infusion rose from 17.2 +/- 1.6 ng/l (3.8 +/- 0.35 pmol/l) to 31.7 +/- 4.2 ng/l (7.0 +/- 0.92 pmol/l) at 40 min after injection of the antagonist, the difference to the control-group (increment from 16.5 +/- 1.2 ng/l (3.6 +/- 0.26 pmol/l) to 41.8 +/- 3.5 ng/l) (9.2 +/- 0.77 pmol/l) being significant (p less than 0.05). Peak plasma cortisol levels were 323 +/- 42 and 529 +/- 52 nmol/l, respectively (p less than 0.05). We then tested the compound in the same subjects during an insulin-induced hypoglycemia; 30 min after administration of 10 micrograms/kg of the AVP antagonist or placebo, all subjects received 0.12 IU/kg of normal insulin, thus inducing a fall of blood glucose levels below 2 mmol/l. The AVP antagonist caused a moderate but insignificant reduction of the rise in plasma ACTH and a slightly greater, significant reduction of the increment in plasma cortisol (350 +/- 19 nmol/l with antagonist and 469 +/- 90 nmol/l with placebo, p less than 0.05) during insulin-induced hypoglycemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of incremental infusions of arginine vasopressin on adrenocorticotropin and cortisol secretion in man.

Arginine vasopressin (AVP) regulates ACTH release under certain conditions, and exogenously administered AVP is used clinically to stimulate ACTH secretion. We attempted to determine at what plasma concentration AVP can stimulate ACTH release. Six normal men were given infusions of AVP (Ferring) or vehicle between 1600 and 1700 h on five occasions: 1) saline (30 mL/h); 2) 10 ng AVP/min; 3) 30 ng AVP/min; 4) 100 ng AVP/min; and 5) 300 ng AVP/min. Plasma AVP, ACTH, and cortisol concentrations were measured every 10 min during the infusions. Basal plasma AVP levels were less than 1 ng/L (less than 0.92 pmol/L). The lowest AVP dose raised plasma AVP into the range found in fluid-deprived subjects (7-8 ng/L;6.5-7.3 pmol/L), but had no effect on plasma ACTH concentrations. AVP in a dose of 30 ng/min also had no effect. The 100 ng AVP/min dose raised plasma AVP concentrations to 51.4-65.5 ng/L (46-60 pmol/L). This increase led to a transient insignificant increase in plasma ACTH from 13.9 +/- 1.2 (+/- SEM) ng/L (3.1 +/- 0.3 pmol/L) to 20.0 +/- 1.4 ng/L (4.4 +/- 0.3 pmol/L), while plasma cortisol rose significantly from 146 +/- 10 to 209 +/- 19 nmol/L (P less than 0.01) after 60 min of infusion. The 300 ng AVP/min dose raised plasma AVP levels to about 260 ng/L (239 pmol/L); the maximal plasma ACTH and cortisol levels were 39.5 +/- 5.0 ng/L (8.7 +/- 1.1 pmol/L; P less than 0.01) and 348 nmol/L (P less than 0.01), respectively. Thus, peripheral plasma AVP levels have to be raised high above the physiological range before ACTH release is stimulated. We conclude that any AVP reaching the adenohypophysis through the peripheral circulation is of much less importance for the regulation of ACTH secretion than is AVP derived from the pituitary portal circulation.

Effects of osmotically stimulated endogenous vasopressin on basal and CRH-stimulated ACTH release in man.

Two groups of six healthy young males participated in separate experiments to examine the physiological role of endogenous vasopressin in h-CRH-induced (100 micrograms iv) ACTH release: a) after drinking of 3500 ml of water; b) after thirsting for 23 h; c) after 0.9% saline infusion, and d) after 5.0% saline infusion (0.06 ml/kg per min for 120 min). AVP levels were markedly elevated (4 ng/l) after thirsting and 5% saline infusion when compared with water loading or infusion of physiological saline. Although basal and h-CRH-stimulated ACTH and cortisol levels tended to be higher during hypertonic saline infusion and dehydration, no significant difference was observed between states of high or low endogenous AVP levels. These results are not in accordance with previous studies using ovine CRH, which might be due to its longer half-time or the timing of the changes in AVP plasma levels in relation to the CRH injection. Our data suggest that the osmotic modulation performed in this study results in AVP concentrations in the adenohypophysis, which are in the threshold range for influencing ACTH release induced by exogenous h-CRH.