Differential chemotactic activities of sensory neuropeptides for human peripheral blood mononuclear cells.

We studied the chemotactic effects of calcitonin gene-related peptide, vasoactive intestinal peptide, substance P (SP), and secretoneurin on PBMC and PBL using micropore filter assays. All four peptides induced migration of PBMC, whereas only calcitonin gene-related peptide, vasoactive intestinal peptide, and SP were chemotactic for PBL. Secretoneurin, known to induce monocyte chemotaxis, was unable to affect lymphocyte migration. Effects of SP on PBL were characterized by checkerboard analyses and represented true chemotaxis. Both T and B cells responded chemotactically to SP, the functional activity of SP residing in its C-terminal amino acid sequence. Involvement of neurokinin (NK) receptors was supported by inhibition of SP-induced migration of PBL with an NK1 receptor antagonist and induction of migration with [Sar9, Met(O2)11]SP and [PyrGlu6, Pro9]SP(6-11), two specific agonists for NK1 receptors, but not with [beta-Ala8]NK A(4-10), an agonist for NK2 receptors. PBL chemotaxis to SP was abolished by inhibition of tyrosin kinase but not by that of protein kinase C. Preincubation of PBL with pertussis or cholera toxin inhibited SP chemotaxis, indicating that in PBL, NK receptors for chemotaxis probably are coupled with G protein and involve a tyrosin kinase signaling pathway. We conclude that, together with calcitonin gene-related peptide and vasoactive intestinal peptide, SP is a lymphocyte chemoattractant, whereas secretoneurin, which is coreleased from sensory nerve endings, is not.

Induction of endothelial cell differentiation into capillary-like structures by substance P.

Angiogenesis is an important process in inflammatory diseases and wound healing. We observed that the proinflammatory neuropeptide, substance P, stimulated angiogenesis in an in vitro model using human umbilical cord vein endothelial cells cultured on a basement membrane (Matrigel) substrate. Substance P stimulated endothelial cell differentiation into capillary-like structures in a dose-dependent manner. Stimulation of endothelial cell differentiation is a newly recognized biological function of substance P. The increased levels of substance P found in chronic inflammatory conditions may play an important role in tissue repair by promoting the development of new vessels and thus achieving compensation for ischemia.

[Kallikrein (urine) in pregnancy-induced hypertension]. / Kallikrein (Harn) bei schwangerschaftsinduzierten Hochdruckerkrankungen.

Total, active and inactive renal kallikrein were compared between 25 patients with hypertensive disorders of pregnancy and 25 healthy pregnant women of corresponding gestational age. Values of all three fractions were twice as high in healthy women than in hypertensive patients and differed with statistical significance. A longitudinal examination of renal kallikrein during pregnancy showed a physiological decrease of values from the 16th-20th week until term. Asymptomatic women, who developed hypertension later on, showed decreased renal kallikrein values.

Human chorionic gonadotrophin: a chemoattractant for human blood monocytes, neutrophils and lymphocytes.

Treatment of rats with human chorionic gonadotrophin (hCG) induced in the testes an inflammation-like reaction characterized by migration of leukocytes into the interstitial space. In order to find out whether hCG acts in a direct manner in this process, we tested peripheral human blood leukocyte attraction by hCG in vitro. Chemotaxis through cellulose nitrate to gradients of test substances was measured using a 48-well microchemotaxis chamber. Human CG was found to be a potent attractor of neutrophils, monocytes and lymphocytes in vitro in the picomolar concentration range. Checkerboard analyses revealed that the type of migration depends on positive concentration gradients of hCG. The chemoattractant nature of hCG is consistent with its having a role to play in regulation of tissue accumulation of these cells within the reproductive tract.

Inhibition of superoxide anion release from circulating neutrophils by L-arginine in man.

In animal studies of myocardial ischemia/reperfusion L-arginine reduces necrotic injury by preservation of endothelial function and attenuation of neutrophil accumulation in ischemic cardiac tissue. Because release of oxygen radical species by circulating neutrophils is important in endothelial function and ischemia-reperfusion injury, this study investigated the effect of intravenous administration of L-arginine on the in vitro release of superoxide anion of neutrophils in healthy young adults. Neutrophils were obtained at various time points before, during, and after infusion of L-arginine (17 mg kg-1 min-1 for 30 min) and analyzed for superoxide dismutase inhibitable reduction of ferricytochrome c. The spontaneously occurring respiratory burst of polymorphonuclear leukocytes at basal conditions was compared with that after triggering by 1 mumol/l formylpeptide or 50 ng/ml phorbolester. Infusion of L-arginine inhibited both basal (P < 0.01) and formylpeptide-triggered (P < 0.05) release of superoxide anion did, but not affect release stimulated by phorbol 12-myristate 13-acetate. Pretreatment of neutrophils with 1 mmol/l L-arginine in vitro also significantly reduced formylpeptide-triggered (1 mumol/l) superoxide anion release, suggesting that the affects observed after in vivo pretreatment may be due to direct action of L-arginine on neutrophils. These findings demonstrate the ability of L-arginine to reduce release of oxygen radical species by circulating neutrophils in man.

Stimulation of the chemotactic migration of human fibroblasts by substance P.

Neuropeptides exert a variety of modulatory effects on inflammatory cellular responses. In order to investigate further activities of these cytokines on mechanisms in inflammatory processes, we determined the ability of substance P to promote human fibroblast chemotaxis. Cell migration was measured by two different assay types in modified Boyden chambers. Substance P was found to be a potent chemoattractant for human fibroblasts in vitro, eliciting a concentration-dependent migratory response. In further investigations we tested the chemoattractant potency of the fragments substance P-(1-4) and substance P-(3-11). As only the C-terminal analog promoted migratory responses, we suggest that the chemotactic responsiveness is largely encoded by the C-terminus of the neuropeptide, which is known to be active on neurokinin receptors. Involvement of neurokinin receptors of type 1 in the chemotactic response to substance P was indicated by fibroblast migration toward optimal concentration of a selective NK1 receptor agonist but not a NK2 receptor agonist. The observed ability of human fibroblasts to respond chemotactically to substance P elucidated another proinflammatory activity of this neuropeptide.

Hemolysis in hypertensive disorders of pregnancy.

The hemolysis markers LDH, haptoglobin, bilirubin (serum, urine), urobilinogen (urine), fragmentocytes and free hemoglobin were compared in 166 patients with various degrees of hypertensive disorders of pregnancy and 179 nonhypertensive pregnant controls in a weekly screening program. Early recognition of hemolysis was limited to a period of 1 week before the actual delivery date. In the diagnostic sensitivity, haptoglobin and to a lesser degree unspecific LDH were clearly superior to the other hemolysis parameters. A decreasing platelet count also has to be taken as an indicator of impending hemolysis. Subclinical hemolysis was associated with poorer fetomaternal outcome. With the aid of haptoglobin, LDH and thrombocytes, an incipient HELLP syndrome could be recognized 1-2 days before the complete clinical picture became apparent.

Low-dose aspirin in primigravidae with positive roll-over test.

In a prospective, randomized, double-blind study for the prevention of pregnancy-induced hypertension and preeclampsia, 41 primigravidae with positive roll-over test (28th-32nd week of pregnancy) received 80 mg aspirin/day or placebo until the end of the 37th week. In the patients treated with acetylsalicylic acid (n = 22), 3 cases of proteinuria occurred, but no hypertensive pregnancy complication. In the placebo group (n = 19), 10 patients developed pregnancy-induced hypertension (6 of them preeclampsia). Group-specific differences concerning the occurrence of hypertension were statistically highly significant (p = 0.0004). No relevant differences were observed with regard to pregnancy duration, birth weight and umbilical artery pH value. The placebo group included 1 intrauterine death. No increased tendency to maternal or fetal bleeding was noticed.