Origin of angiotensin in human leukocytes

The capability of human leukocytes to synthesize angiotensin peptides was studied. Leukocytes which were prepared from heparinized blood by sedimentation in dextran were incubated for 0, 1, 2, 4, 6, 8, and 24 h at 37 degrees C with the 3H-labeled amino acid isoleucine. At the various time points the washed cells were extracted with 0.1 M acetic acid. The extracts contained radioactive material which eluted from a Bio Sil TSK 125 gel filtration column in the low-molecular-weight range with the same retention time as synthetic angiotensin I (ANG I) or angiotensin II (ANG II). The extracted radioactive material also bound to anti-ANG I and anti-ANG II antibodies. However, excess of unlabeled synthetic ANG I or ANG II failed to displace the bound radioactivity. Rechromatography of the radioactive material which eluted in the low molecular weight fractions of the gel filtration column could be characterized as non-incorporated 3H-isoleucine on a reversed phase C18 column with an acetonitrile gradient. These findings demonstrate the lack of an angiotensin-generating pathway in human leukocytes. Further studies are necessary to determine the origin of angiotensin peptides in human leukocytes.

Association between the renin angiotensin system and anaphylaxis

Patients with hymenoptera venom anaphylaxis before immunotherapy (n = 50) showed significantly lower renin, angiotensinogen, angiotensin I and angiotensin II as compared to healthy non-allergic controls (n = 25) (p < 0.05). A significant inverse correlation between the severity of clinical symptoms and the plasma levels of renin, angiotensinogen, angiotensin I and angiotensin II was found: the lower the levels the more severe the clinical symptoms. Hymenoptera venom allergic patients with repeated anaphylactic reactions during hyposensitizatin did not tolerate the sting of a living insect (n = 6). Sting provocation with a living insect induced clinical symptoms of anaphylaxis in all of the 6 patients. Renin, angiotensinogen, angiotensin I and II remained significantly lower in these patients as compared to healthy non-allergic controls. Likewise, no stimulation of the renin angiotensin system occurred during the anaphylactic reaction. The values of angiotensin II were similar or lower than the values before the anaphylactic reaction. In contrast, patients with successful immunotherapy (n = 27) who tolerated the sting of a living insect, renin, angiotensin I and II were significantly higher than in patients without immunotherapy. After immunotherapy, the values for renin, ANG I and ANG II were similar to the values found in healthy non-allergic controls. Patients with a history of hymenoptera venom anaphylaxis (n = 22) showed significantly lower ANG II concentrations in their leukocytes as compared to healthy non-allergic controls (n = 24). Successful immunotherapy induced a significant 9-fold increase in ANG II as compared to patients without immunotherapy. These findings suggest a possible role of the renin angiotensin system in hymenoptera venom anaphylaxis.

Contamination of heparin by histamine: measurement and characterization by high-performance liquid chromatography and radioimmunoassay

Plasma samples which were collected in the presence of heparin contained 12.83 +/- 0.34 ng/ml histamine-immunoreactive material (n = 10). In contrast, histamine-immunoreactive material in plasma samples which were collected in the presence of EDTA/phenanthroline contained 0.32 +/- 0.01 ng/ml (n = 10). Histamine-immunoreactive material was found as a contaminant in three different heparin formulations with unrelated batch numbers. The concentrations of the histamine-like material were 32.82, 81.93, and 280.23 ng/ml, respectively. Octadecasilyl-silica (ODS) cartridges were used to purify histamine from other constituents in the heparin preparations. The histamine-immunoreactive material in the three preparations could be characterized as histamine with cation-exchange high-performance liquid chromatography (HPLC) on a TSK SP-5 PW column with NaH2PO4, pH5.0, as a mobile phase and gradient elution. For the accurate measurement of histamine in plasma samples with heparin as an anticoagulant, one should be aware of a possible contamination of heparin formulations by histamine.

Histamine, tryptase, norepinephrine, angiotensinogen, angiotensin-converting enzyme, angiotensin I and II in plasma of patients with hymenoptera venom anaphylaxis

Markers of immediate-type hypersensitivity such as histamine and tryptase were measured in the plasma of nonallergic volunteers and patients with a history of hymenoptera venom anaphylaxis. No significant differences in histamine or tryptase were found between patients and controls. Norepinephrine, an important compound involved in the control of cardiovascular functions and blood pressure, was the same in patients and nonallergic volunteers. In addition, components of the renin-angiotensin system were determined. Patients with hymenoptera venom anaphylaxis showed significantly lower plasma angiotensinogen concentrations as compared to healthy nonallergic controls (p < 0.007), whereas plasma ACE activity was the same. Likewise, the plasma levels of angiotensin I and angiotensin II were significantly reduced in patients as compared to controls (p < 0.04 and p < 0.003, respectively). These findings suggest that the renin-angiotensin system may play an important role as a counteracting factor in hymenoptera venom anaphylaxis.

Increased urinary excretion of angiotensin during anaphylactoid reactions

Immunoreactive angiotensin I (ANG I) and angiotensin II (ANG II) were measured in human urine, after purification on octadecasilyl-silica cartridges. The total daily excretion of ANG I and II in healthy volunteers was 292.2 +/- 62.5 and 12.2 +/- 2.5 pmol/24 h (mean +/- SEM; n = 14). No differences in the concentrations of ANG I or II were detected between females and males. Although lower levels of ANG I and II were found during the nighttime, no clear-cut circadian rhythm in the excretion of the peptides was found. ANG II was not degraded in acidified urine which shows the effective inhibition of ANG-II-degrading enzymes. Oral provocation tests (OPT) in patients with a history of anaphylactoid reactions (AR) to drugs, foods and food additives were associated with elevated ANG I and II concentrations when symptoms of anaphylaxis occurred. The excretion of ANG I increased by a factor of 7.8 +/- 2.4 and the excretion of ANG II by a factor of 6.1 +/- 1.6 (mean +/- SEM; n = 15). In patients with negative OPT and no clinical symptoms of anaphylaxis, the levels of ANG I and II remained unchanged (n = 26). It is concluded that angiotensin peptides play a role during the events of AR. The peptides may be considered as counteracting factors which stabilize cardiovascular functions.

Human leukocytes contain angiotensin I, angiotensin II and angiotensin metabolites

Angiotensin I (ANG I) and angiotensin II (ANG II) were measured radioimmunologically in human leukocytes extracted with a mixture of acetone, 1N HCl and water (40:1:10 vol). The analytical recoveries of 125I-ANG I and 125I-ANG II, which were added prior to extraction, were 92.00 +/- 3.10 and 99.19 +/- 0.91% (mean +/- SEM; n = 12). The concentration of ANG I- and ANG II-like material in leukocytes from healthy volunteers was 32.04 +/- 3.64 and 13.05 +/- 1.26 fmol/mg protein (n = 24). The immunoreactive material could be characterized on HPLC as Ile5-ANG I, Ile5-ANG II and angiotensin metabolites such as Ile4-ANG III, Ile3-ANG II hexapeptide, Ile2-ANG II pentapeptide and Ile1-ANG II tetrapeptide. From the ANG I-immunoreactive material determined in the extracts, 26% could be characterized on HPLC as Ile5-ANG I. The ANG II-immunoreactive material present in the extracts could be separated on HPLC into 44% Ile5-ANG II, 14% Ile4-ANG III, 7% Ile3-ANG II hexapeptide, 4% Ile2-ANG II pentapeptide and 8% Ile1-ANG II tetrapeptide. Patients with a history of anaphylactic reactions to bee or wasp venom showed significantly reduced ANG II concentrations in their leukocytes as compared to controls (6.76 +/- 0.76 fmol ANG II/mg protein, n = 22, vs. 13.05 +/- 1.26 fmol ANG II/mg protein, n = 24; p < 0.05). A significant correlation between the severity of clinical symptoms and the ANG II levels was found for grade I and II reactions (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma concentrations of arginine vasopressin, oxytocin and angiotensin in patients with hymenoptera venom anaphylaxis

The plasma concentrations of arginine vasopressin, oxytocin, angiotensin I and II were studied in patients with hymenoptera venom anaphylaxis (n = 50) and healthy volunteers (n = 25). There was no difference in arginine vasopressin: 5.52 +/- 0.45 fmol/ml vs. 3.99 +/- 0.41 fmol/ml or oxytocin: 28.10 +/- 1.13 fmol/ml vs. 26.24 +/- 1.80 fmol/ml between patients and controls. No correlation between the severity of clinical symptoms and the plasma levels of arginine vasopressin and oxytocin was found in patients. However, patients with a history of hymenoptera venom anaphylaxis showed significantly reduced angiotensin I and angiotensin II plasma levels as compared to controls (ANG I: 9.51 +/- 0.61 fmol/ml vs. 22.91 +/- 1.73 fmol/ml; ANG II: 2.84 +/- 0.16 fmol/ml vs. 6.95 +/- 0.33 fmol/ml). A significant inverse correlation between the severity of clinical symptoms and the plasma levels of angiotensin I and angiotensin II was observed; the lower the concentrations the more severe the clinical symptoms. Oxytocin immunoreactivity eluted from the HPLC column as a single peak with the same retention time as synthetic oxytocin. The vasopressin immunoreactive material could be characterized on HPLC as arginine-vasopressin and two other peptides of unknown nature which crossreacted with the vasopressin antibody. These findings suggest a possible role of angiotensin I and angiotensin II in hymenoptera venom anaphylaxis while arginine vasopressin and oxytocin are most likely not involved.

The renin angiotensin system and hymenoptera venom anaphylaxis

Components of the renin angiotensin system, namely renin, angiotensinogen, angiotensin I and II and aldosterone were measured in plasma of patients with hymenoptera venom anaphylaxis (n = 50) and healthy non-allergic controls (n = 25). Patients with a history of anaphylactic reactions to hymenoptera venom who did not undergo immunotherapy showed significantly reduced renin, angiotensinogen, angiotensin I and angiotensin II in plasma as compared with controls (P < 0.05). There was no difference in the aldosterone concentration between patients and controls. Angiotensin I, angiotensin II, renin and angiotensinogen levels were the same in male and female patients. There was also no difference in the angiotensin I, II, renin or angiotensinogen levels between young and older patients. A significant inverse correlation between the severity of clinical symptoms and the plasma levels of renin (r = -0.382, P < 0.001), angiotensinogen (r = -0.567, P < 0.0001), angiotensin I (r = -0.656, P < 0.0001) and angiotensin II (r = 0.0762, P < 0.0001) was found: the lower the levels the more severe the clinical symptoms. No correlation was found for aldosterone. Hymenoptera venom allergic patients with repeated anaphylactic reactions during hyposensitization did not tolerate the sting of a living insect (n = 6). In these patients, renin, angiotensinogen, angiotensin I and II remained significantly lower than in healthy non-allergic controls. Patients with successful immunotherapy (n = 27) who tolerated the sting of a living insect had renin, angiotensin I and II significantly higher than patients without immunotherapy. These findings suggest a possible role of the renin angiotensin system in hymenoptera venom anaphylaxis.

Measurement and characterization of histamine and methylhistamine in human urine under histamine-rich and histamine-poor diets

A radioimmunoassay for histamine was used to measure histamine and 1-methylhistamine (MH) in human urine samples. The detection limit of this assay was 2 ng/ml for histamine and 0.5 ng/ml for MH. Cation exchange high performance liquid chromatography (HPLC) on a Bio-Gel TSK SP-5 PW column with gradient elution was capable of separating histamine from its precursor L-histidine and its metabolites MH and 1-methylimidazole acetic acid (MIAA). The concentration of MH-immunoreactive materials in healthy volunteers with no dietary restrictions was 202 +/- 92 micrograms/24 h (mean +/- SD; n = 14). The excretion of MH-like material, expressed as micrograms of MH per 24 h, was not significantly different before or after the intake of histamine-rich food: 217 +/- 88 vs. 276 +/- 135 micrograms/24 h (n = 10). However, in urine samples collected in individual fractions, the levels of MH immunoreactivity were significantly increased after a histamine-rich meal in comparison to the corresponding fractions which were taken a day earlier at the same time intervals after a histamine-low diet (p < 0.03). HPLC characterization of MH immunoreactivity revealed the presence of histamine, MH and a compound with the same retention time as MIAA. The ratio of histamine, MH and MIAA in controls without dietary restrictions, as determined by HPLC analysis, was 50 +/- 6, 47 +/- 5 and 3 +/- 1%, respectively. After a histamine-rich meal the ratio was 97 +/- 2% for histamine, 1% for MH and 2 +/- 1% for MIAA.

Urinary excretion of angiotensin I, II, arginine vasopressin and oxytocin in patients with anaphylactoid reactions

Human urine samples, purified on octadecasilyl-silica cartridges, contained immunoreactive angiotensin I, II, arginine vasopressin and oxytocin. The daily excretion of these peptides in healthy volunteers was 190.00 +/- 38.43 (n = 12), 17.48 +/- 3.09 (n = 12), 63.43 +/- 14.84 (n = 8) and 13.52 +/- 1.42 (n = 7) pmol/24 hr, respectively (mean +/- s.e.m.). Patients with a history of anaphylactoid reactions to drugs or food additives showed clinical symptoms such as urticaria, flush, nausea, dizziness and hypotension after oral provocation with cyanocobalamine, propyphenazone, acetylsalicylic acid and sodium benzoate. In five of the seven patients, angiotensin I and II were increased several fold in the urine fractions after symptoms were reported. The average increase in the urine concentration of both peptides was fourfold and 5.5-fold. In three out of five patients, the mean excretion of arginine vasopressin and oxytocin immunoreactive material was also elevated by a factor of 5.7 and 4.4, respectively. Oral provocation with a placebo failed to elicit anaphylactoid symptoms or an increase in the urine levels of angiotensin I or angiotensin II. Angiotensin I and angiotensin II-like immunoreactivity could be characterized on HPLC as Ile5-angiotensin I, Ile5-angiotensin II and angiotensin II metabolites. HPLC characterization of immunoreactive arginine vasopressin and oxytocin in two different gradient systems showed retention times different than the retention times of the corresponding synthetic standard peptides indicating that both peptides are not authentic AVP and OXT. These results suggest that angiotensin I and angiotensin II may be involved in the clinical events observed during some forms of anaphylactoid reactions.

Presence of angiotensin peptides in human urine

Immunoreactive angiotensin I and angiotensin II were found in human urine that was purified on octadecasilylsilica cartridges. The daily excretion of angiotensin I and II in healthy volunteers was 189.00 (SE 38.36) and 17.54 (SE 3.07) pmol/24 h or 148.09 (SE 32.22) and 12.82 (SE 2.34) pmol/L, respectively (n = 12). No circadian rhythm was observed in the excretion patterns of angiotensin I and II. In vitro degradation of angiotensin I or II could not be detected in acidified urine samples. A marked increase in the excretion of angiotensin I and II could be demonstrated in patients with anaphylactoid reactions to drugs and food additives after oral challenge. Immunoreactive angiotensin I and II could be characterized by HPLC as Ile5-angiotensin I, Ile5-angiotensin II, and angiotensin II metabolites.

Presence of Angiotensin Peptides in Human Urine

Immunoreactive angiotensin I and angiotensin II were found in human urine that was purified on octadecasilylsilica cartridges. The daily excretion of angiotensin I and II in healthy volunteers was 189.00 (SE 38.36) and 17.54 (SE 3.07) pmol/24 h or 148.09 (SE 32.22) and 12.82 (SE 2.34) pmol/L, respectively (n = 12). No circadian rhythm was observed in the excretion patterns of angiotensin I and II. In vitro degradation of angiotensin I or II could not be detected in acidified urine samples. A marked increase in the excretion of angiotensin I and II could be demonstrated in patients with anaphylactoid reactions to drugs and food additives after oral challenge. Immunoreactive angiotensin I and II could be characterized by HPLC as Ile5-angiotensin I, Ile5-angiotensin II, and angiotensin II metabolites.

Antibodies against terminal galactosyl (alpha 1-3) galactose epitopes in systemic sclerosis (scleroderma)

Sera from 224 patients with systemic sclerosis (scleroderma) were analyzed for circulating antibodies against an antigenic determinant characterized by two molecules of galactose in alpha 1-3 linkage. About 45% of the patients were found to have values above the normal range. The mean antibody level was significantly higher than that found in normal subjects (p less than 0.001) or in patients with primary Raynaud's phenomenon who were included as controls. The mean level of anti-Gal antibodies correlated with the degree of skin and internal organ involvement, as well as with the presence of progression or inflammation. Furthermore, when patients with early onset disease were analyzed, high levels of anti-Gal antibodies were present in the subgroups characterized by evidence of progression or inflammation, whereas patients with stable disease did not differ from the controls. We conclude that humoral immunity against Gal alpha 1-3 Gal is an early feature of scleroderma, may be important for its pathogenesis, and may provide a more sensitive tool to detect disease activity.

A naturally occurring opioid peptide from cow's milk, beta-casomorphine-7, is a direct histamine releaser in man

beta-Casomorphine-7, a naturally occurring product of cow's milk with opiate-like activity, was studied for possible direct histamine liberation activities in humans. It was found to cause concentration-dependent in vitro histamine release from peripheral leukocytes of healthy adult volunteers. Intradermal injection of beta-casomorphine-7 induced a wheal and flare reaction in the skin similar to histamine or codeine. Oral pretreatment with the H1 antagonist terfenadine significantly inhibited the skin responses to beta-casomorphine-7. The intradermal injection of an opiate receptor antagonist, naloxone, inhibited in vitro histamine release and skin reactions only in a 100-fold excess over beta-casomorphine-7. These findings suggest that beta-casomorphine-7 can be regarded as a noncytotoxic, direct histamine releaser in humans. The clinical relevance of these findings deserves further studies.

In vitro IgE eluation and histamine releasability from peripheral leukocytes of atopics and normals

The relation between the amount of cell-bound IgE and the histamine 'releasability' of peripheral leukocytes was studied in 28 patients with atopic diseases and 26 non-atopic controls after in vitro stimulation with anti-IgE. Cell-bound IgE was eluted in acid buffer (pH 3.7) and the amount of histamine released (HR) into supernatant at this pH was measured. Incubation with acetate buffer (pH 3.7) induced significantly higher spontaneous HR (32 net percent) in atopics compared to 18% in controls. The amount of IgE eluted was significantly higher in atopics: The calculated number of IgE molecules/basophil was 332,000 in atopics compared to 177,000 in controls. There was a significant positive correlation between plasma IgE and in vitro elutable IgE in atopics (r = 0.73) compared to controls (r = 0.24). After a careful washing procedure attempts were made to 'resensitize' the basophils through incubation with autologous plasma or standard IgE solutions. When resensitization was possible, there was no correlation between histamine releasability after resensitization and original IgE content of basophils. It is concluded that the increased histamine releasability from leukocytes of atopic individuals after stimulation with anti-IgE is only in part due to an increased number of IgE molecules per basophil surface. A non-specific increased releasability was demonstrated by increased spontaneous HR rates in acid buffer (pH 3.7). A resensitization with autologous plasma-IgE was possible only in half of the subjects investigated, most of them being atopic. The data support the concept of an altered releasability both towards IgE-dependent and independent stimuli being one possible factor in the pathogenesis of atopic eczema.