HISTAMINE-FORMING CAPACITY OF MULTIPLYING CELLS

Suppression of melanoma cell proliferation by histidine decarboxylase specific antisense oligonucleotides

Histidine decarboxylase (HDC) is expressed by the cells of melanoma, in which the histamine content tends to be relatively high. This study shows that elevated expression of HDC was found by western blot analysis of primary and metastatic melanoma tissue using a polyclonal HDC specific antibody. The specificity of anti-HDC antibody was confirmed by inhibition of HDC translation (i.e., immunopositivity) in melanoma cells by HDC-specific antisense oligonucleotide. Moreover, the decrease in proliferation caused by HDC antisense oligonucleotides indicates considerable functional relevance of histamine synthesis in melanoma growth and suggests a possible in situ application of specific antisense oligonucleotides for HDC in melanoma therapy.

Expression analysis of the histamine H(3) receptor in developing rat tissues

Endogenous histamine is involved in tissue growth and cell proliferation. In accordance with a putative function of the H(3) receptor in this mitogenic effect, we show that H(3)-receptor mRNAs are expressed together with those of the histamine-synthesizing enzyme in the embryonic liver and adipose tissue, and in various epithelia. Finally, we show that activation of recombinant H(3) receptors enhances MAP kinase activity.

Evidence of a dual role of endogenous histamine in angiogenesis

The specific activation of mast cells in situ causes vigorous local mast-cell mediated angiogenesis (MCMA). The mast cell is a major source of histamine and, as recently reported, specific histamine H1- and H2-membrane receptor antagonists are able individually to significantly suppress MCMA in rats, as assessed using the mesenteric window angiogenesis assay (MWAA). In addition to membrane receptors for histamine, a type of intracellular histamine receptors, designated Hic, has been described. It is now demonstrated that the potent Hic-receptor antagonist DPPE (N,N-diethyl-2-[4-(phenylmethyl)phenoxy]ethanamine HCl), administered parenterally, stimulates MCMA significantly in rats, as quantified by the MWAA. Although the target cell(s) are not known, there are several ways by which their Hic receptors could be activated: uptake of histamine released from mast cells, mobilization from preformed cytoplasmic and nuclear stores, and production of de novo histamine by histidine decarboxylase activity. The fact that the occupancy by histamine of H1- and H2-membrane receptors stimulates MCMA and the occupancy by histamine of Hic inhibits MCMA suggests that endogenous histamine is capable of regulating angiogenesis by a dual mode of action. This is apparently the first report ascribing a dual role of this type in angiogenesis to a single molecule.

Growth of cultured human glioma tumour cells can be regulated with histamine and histamine antagonists

The 50% survival time for low grade astrocytomas is 50 months and for high grade astrocytomas it is 13 months, underlining the need for new therapies. Several reports show that in vivo histamine antagonists cause retardation of tumour growth in some animal models and prolonged survival in cancer patients. Therefore we have tested the growth modulating effects of histamine and histamine antagonists on human glioma cultures. Twelve freshly excised human gliomas were cultured and tested for their in vitro sensitivity to histamine and histamine antagonists. Four continuous glioma cell lines were used to confirm the glioma-specificity of the effects observed in the primary cell lines. In low serum concentration (0 or 1%) the growth of 5/9 primary glioma-derived cultures could be stimulated with 0.2 mM histamine, and in 4/5 cases with 0.2 microM histamine. One mM of the histamine H2-receptor antagonist cimetidine could inhibit the growth of 4/5 primary glioma cultures when tested in 1% human AB serum, and of 6/13 cases when tested in 1% FCS. Lower concentrations (down to 1 microM) were less effective. The histamine H1-receptor antagonist pyrilamine gave variable results. The specificity of the effects is indicated by the absence of a generalised toxic effect, by the observation that the antagonist-induced inhibition could be reversed with histamine, and by the correlation of the obtained cimetidine-induced growth inhibition with the maximal growth rate of the primary cell lines in 10% FCS. The observed cimetidine-induced inhibition of the in vitro proliferation of gliomas suggests that cimetidine is a relevant candidate for the in vivo growth inhibition of these tumours.

Visualization of histamine binding to nuclei

The binding of histamine to cultured microvascular endothelial cells and glycol methacrylate embedded ovarian tissue sections has been localized using fluorescein-albumin-histamine conjugate. Histamine conjugate was bound to the plasma membranes and nuclei of luteal, endothelial, and ovarian stromal cells. An apparent increase in the binding of histamine to nuclei was observed in the presence of cimetidine but the plasma membrane staining was still evident. Unlike cimetidine, pyrilamine completely inhibited the binding of histamine to the plasma membrane. Instead, in the presence of pyrilamine, histamine bound exclusively to the nuclei of endothelial, germinal epithelial, granulosa, and stromal cells. However, the nuclei of terminally differentiated luteal cells and oocytes were not labeled. The functional significance of these nuclear histamine binding sites remains to be determined.

Effect of lipopolysaccharides on histamine synthesis by hematopoietic cells

We show herein that lipopolysaccharides (LPS), in vitro, synergize with GM-CSF to increase histamine synthesis by murine bone marrow cells. LPS has no effect on its own and does not potentiate histamine synthesis promoted by IL-3, the only other cytokine sharing this biological activity with GM-CSF. Despite the fact that GM-CSF and LPS synergistically increase PGE2 levels, the potentiating effect of LPS does not require PGE2 that have been previously shown to enhance GM-CSF-induced histamine synthesis. We provide evidence that this effect of LPS on histamine production by bone marrow cells is mediated by the intracellular cAMP transduction signal. In addition, LPS and cAMP enhance GM-CSF-induced histidine decarboxylase activity, showing that both substances act on histamine synthesis. Contrary to in vitro results, LPS injection into mice induces an increase in both intracellular histamine and HDC activity in bone marrow cells. Our results support the conclusion that this effect is mediated by GM-CSF. In conclusion, LPS appears to be a powerful HDC inducer in hematopoietic organs because of its ability, on one hand, to induce circulating GM-CSF and, on the other hand, to potentiate GM-CSF induction of HDC.

Histamine is an intracellular messenger mediating platelet aggregation

Inhibition of human platelet aggregation by N,N-diethyl-2-[4-(phenylmethyl)phenoxy]ethanamine-HCl (DPPE), a novel antagonist of histamine binding, suggested that histamine might serve a critical role in cell function. Phorbol-12-myristate-13-acetate (PMA) or collagen was found to increase platelet histamine content in parallel with promotion of aggregation. Inhibitors of histidine decarboxylase (HDC) suppressed both aggregation and the elevation of histamine content, whereas DPPE inhibited aggregation only. In saponin-permeabilized platelets, added histamine reversed the inhibition by DPPE or HDC inhibitors on aggregation induced by PMA or collagen. The results indicate a role for histamine as an intracellular messenger, which in platelets promotes aggregation.

Diamineoxidase activity and tissue histamine content of human skin, breast and rectal carcinoma

In view of the controversy that exists regarding the histamine content and diamine oxidase activity in relation to human carcinomatous growths, the present investigation was undertaken and carcinomatous tissues of skin, breast and rectum were analysed. The result of the experiment gives a clear evidence that both histamine concentration and diamine-oxidase activity increase significantly in all the three types of growth. The result has been discussed and a reasonable explanation has been offered for the observations made.

Change of hepatic histamine content during hepatic fibrosis

Hepatic function was studied by measuring the time courses of several variables in blood and liver using a chronic liver-injury model produced by administering CCl4 consecutively for 12 weeks in rats. A marked increase in liver histamine content occurred after 10 weeks of treatment with CCl4. At weeks 10 and 12, liver histamine levels in the CCl4-treated group were 1.95 and 4.61 times higher, respectively, than in the control group. This change in liver histamine content appeared after that in other variables such as glutamic pyruvic transaminase, alkaline phosphatase, and white blood cells, but it corresponded to a change in liver hydroxyproline. Increased mast cells were seen in fibrotic foci around Glisson's sheath by microscopic morphological observation of the liver 12 weeks after treatment with CCl4. The histamine concentration in plasma tended to decrease after CCl4 treatment, and at week 12 the decrease was statistically significant compared with control. The liver activities of histamine-metabolizing enzymes, histamine-N-methyltransferase and histaminase, decreased to 1/3.4 and 1/6.0 times those of the nontreated group, respectively, 12 weeks after treatment with CCl4, whereas blood histaminase increased about 9.2 times. The increase in histamine content in injured liver was presumedly derived from the increase in mast cells in the inflamed area of the liver; also, the deficiency of histamine-metabolizing enzymes in liver might have caused the high histamine content in the liver. On the other hand, the decrease in plasma histamine concentration might have occurred as a consequence of the enzyme leakage from hepatocytes that accompanied the breakdown of hepatocytes by CCl4 and thus, of the histamine metabolism in blood by the leaked enzymes. The same kind of experiment was performed using a dimethylnitrosamine-induced liver injury model in rats. The increase of hydroxyproline in the liver occurred 11 days after that of histamine content in liver. These results suggest the possibility that increased histamine in the liver may participate in the biosynthesis of collagen.

Therapeutic effect of histidine decarboxylase inhibitor on chronic active hepatitis

The effect of orally administered histidine decarboxylase inhibitor on liver function tests and histological appearance as well as on plasma histamine level were evaluated in biopsy proven 13 patients with chronic active hepatitis, whose liver function tests were refractory to other measures. Tritoqualine was used as histidine decarboxylase inhibitor and was administered in dose levels of 600 to 1,600 mg per day. Before treatment the average value of SGOT, SGPT and plasma histamine showed 252 +/- 24U, 318 +/- 152U and 15.2 +/- 5.5 microgram/L, respectively. Results obtained at six weeks' treatment, however, gave significantly improved values, indicating SGOP 57 +/- 24 (p less than 0.001), SGOP 40 +/- 28 (p less than 0.001) and plasma histamine 8.6 +/- 0.4 (p less than 0.001). Serum gammaglobulin also tended to fall (p less than 0.1). Marked improvement was noted in reexamined biopsied specimen, representing disappearance of fibrogenesis as well as round cell infiltration in and around the portal tract, together with pericellular fibrosis. Four cases have been proven to be healed. Despite long-term administration, no obvious side effect was observed. Investigation for HBsAg revealed to be positive in 4, however, no conspicuous difference was seen from that of negative cases in the improvement.

Histamine and spermidine content in brain during development

Histamine concentration in fetal rat brain is high at 17 days gestation but decreases sharply just before birth. Values subsequently increase to a maximum postnatal concentration 5 to 10 days after birth, and then steadily decline to low adult values by time of weaning. Spermidine follows a pattern similar to that of histamine but with a 24- to 48-hour lag. The developmental pattern for histamine in the central nervous system is different from that for other neural amines. It appears that the marked fetal and neonatal changes in brain histamine correlate best with periods of rapid cell proliferation and growth during brain maturation.