Effect of gefarnate on acute gastric mucosal lesion progression in rats treated with compound 48/80, a mast cell degranulator, in comparison with that of teprenone.

We have reported that teprenone (geranylgeranylacetone), an anti-ulcer drug, prevents acute gastric mucosal lesion progression in rats treated once with compound 48/80 (C48/80), a mast cell degranulator, possibly by suppressing mucus depletion, neutrophil infiltration, and oxidative stress in the gastric mucosa. Herein, we examined the preventive effect of gefarnate (geranyl farnesylacetate), an anti-ulcer drug, on acute gastric mucosal lesion progression in rats treated once with C48/80 (0.75 mg/kg, i.p.) in comparison with that of teprenone, because the chemical structure and anti-ulcer action of gefarnate are similar to those of teprenone. Gefarnate (50, 100 or 200 mg/kg) administered orally at 0.5 h after C48/80 treatment, at which time gastric mucosal lesions appeared, reduced progressive gastric mucosal lesions at 3 h dose-dependently. At 3 h after C48/80 treatment, the gastric mucosa had decreased adherent mucus and hexosamine contents and increased myeloperoxdiase (an index of neutrophil infiltration) and xanthine oxidase activities and thiobarbituric acid reactive substances (an index of lipid peroxidation) content. Post-administered gefarnate attenuated all these changes dose-dependently. These preventive effects of gefarnate were similar to those of teprenone at a dose of 200 mg/kg. Post-administered gefarnate did not affect the increases in serum serotonin and histamine concentrations and the decrease in gastric mucosal blood flow at 3 h after C48/80 treatment like teprenone. These results indicate that orally administered gefarnate prevents acute gastric mucosal lesion progression in C48/80-treated rats possibly by suppressing mucus depletion, neutrophil infiltration, and oxidative stress in the gastric mucosa like teprenone.

Cytotoxic activity of polyprenylalcohols and vitamin K2 derivatives.

Cytotoxic activity of 9 polyprenylalcohols and 6 vitamin K2 derivatives (MK-1 to MK-6) with various lengths of prenyl units was investigated. Among these compounds, geranylgeraniol with 4 prenyl units, and MK-2 with 2 prenyl units, showed the highest cytotoxic activity against human oral tumor cell lines (HSC-2, HSG), without induction of internucleosomal DNA fragmentation. Higher molecular weight compounds showed selective cytotoxicity against tumor cell lines than normal human gingival fibroblasts HGF. ESR spectroscopy showed that all polyprenylalcohols did not produce radical, nor scavenged O2- generated by hypoxanthine and xanthine oxidase reaction, and only slightly enhanced the radical intensity of sodium ascorbate. Vitamin K2 derivatives scavenged O2- more efficiently, but did not produce radical (except MK-3) and only slightly modified the ascorbate radical intensity. Cytotoxic activity of these compounds might be affected by the molecular weight, hydrophobicity, van der Waals area and stabilization of hydration of the molecule.

Gefarnate increases PAS positive cell density in rabbit conjunctiva.

AIMS: The effects of three drugs for the treatment of gastritis and gastric ulcer--gefarnate, ecabet sodium, and troxipide--on periodic acid Schiff (PAS) positive cell density in rabbit conjunctiva in vivo were investigated. METHODS: Eye drops containing gefarnate (0.1%, 1%), ecabet sodium (0.1%, 1%), or troxipide (0.1%, 1%) were instilled in both eyes of rabbits, six times a day for 7 days. On the eighth day, filter paper was gently pressed on the bulbar and palpebral conjunctiva, and impression cytology was performed with PAS staining. Three points in each specimen were selected randomly, and PAS stained cells were counted. RESULTS: The instillation of gefarnate increased PAS positive cell density significantly at the concentration of 1% (p < 0.05). In contrast, instillation of ecabet sodium or troxipide failed to change PAS positive cell density. CONCLUSIONS: These results demonstrated that gefarnate stimulates PAS positive cell density in rabbit conjunctiva.

Vitamin K2 and its derivatives induce apoptosis in leukemia cells and enhance the effect of all-trans retinoic acid.

Geranylgeraniol, a polyprenylalcohol composing the side chain of vitamin K2 (VK2), was previously reported to be a potent inducer of apoptosis in tumor cell lines (Ohzumi H et al, J Biochem 1995; 117: 11-13). We examined the apoptosis-inducing ability of VK2 (menaquinone 3 (MK3), MK4 and MK5) and its derivatives such as phytonadione (VK1), as well as polyprenylalcohols with side chains of various lengths including farnesol (C15-OH; FO), geranylgeraniol (C20-OH; GGO), and geranylfarnesol (C25-OH; GFO) toward leukemia cells in vitro. MK3, MK4, MK5 and GFO (at 10 microM) showed a potent apoptosis-inducing activity for all freshly isolated leukemia cells tested and for leukemia cell lines such as NB4, an acute promyelocytic leukemia (APL)-derived cell line and MDS92, a cell line derived from a patient with myelodysplastic syndrome, although there were some differences depending on the cells tested. In contrast, VK1 showed no effect on any of the leukemia cells. The combination of MK5 plus all-trans retinoic acid (ATRA) resulted in enhanced induction of apoptosis in both freshly isolated APL cells and NB4 cells as compared to each reagent alone. These data suggest the possibility of using VK2 and its derivatives for the treatment of myelogenous leukemias, including APL.

Gefarnate stimulates secretion of mucin-like glycoproteins by corneal epithelium in vitro and protects corneal epithelium from desiccation in vivo.

The effect of drugs for gastritis and gastric ulcer (ecabet sodium, gefarnate, teprenone, and troxipide) on the secretion of mucin-like glycoproteins from rat cornea were investigated in vitro and on a short-term, rabbit dry eye model in vivo. For the studies in vitro, cultured rat cornea sections (3 mm diameter) were incubated with radiolabeled sodium sulfate, rinsed, and then incubated for 30 min in the presence of one of the drugs. The culture media were reacted with Dolichos biflorus agglutinate (DBA)-lectin, and the radioactivity of DBA-bound mucin-like glycoproteins was measured. A cytotoxicity assay confirmed that mucin-like glycoproteins had not leaked from damaged cells. For studies in vivo, eye drop vehicle or drops containing gefarnate were instilled in the eyes of nine anesthetized rabbits, and then the eyes were kept open with specula for two hours. These rabbits and two control rabbits not subjected to ocular drying were killed, and their eyes were enucleated and stained with methylene blue. Corneal epithelial damage from desiccation was evaluated based on the extent of methylene blue staining. Among the four kinds of drugs for gastritis and gastric ulcers, only gefarnate significantly increased the mucin-like glycoprotein secretion from cultured rat corneas in vitro; this stimulatory effect of gefarnate was dose-dependent. In vivo, the instillation of gefarnate reduced corneal epithelial damage from desiccation in a dose-dependent fashion. These results suggest that gefarnate reduces desiccation of corneal epithelium, perhaps by stimulating secretion of mucin-like glycoproteins from corneal epithelium.

Effect of N-(3-aminopropionyl)-L-histidinato zinc (Z-103) on healing and hydrocortisone-induced relapse of acetic acid ulcers in rats with limited food-intake-time.

In the healing test of acetic acid ulcers in rats with limited food-intake-time, Z-103 given, p.o., at doses of 3 and 10 mg/kg, twice a day, for 14 consecutive days from the day after acetic acid injection not only reduced the size and depth of the ulcers, but also promoted the regeneration of the defective mucosa. In the hydrocortisone-induced relapse test of acetic acid ulcers in rats with limited food-intake-time, Z-103 given, p.o., twice a day, at doses of 3 and 10 mg/kg for 20 consecutive days from the 40th day after the acid injection strongly prevented the exfoliation of the regenerated mucosa. Cimetidine (100 mg/kg x 2/day, p.o.), like Z-103, showed a marked relapse-preventive action in addition to the healing-promoting action. However, it was more effective on the healing. Gefarnate (300 mg/kg x 2/day, p.o.) markedly reduced the size and depth of the ulcers and strongly prevented the steroid-induced relapse, but showed no apparent effect on the regeneration of the defective mucosa. These results suggest that Z-103 may be a new therapeutic agent sharing both healing-promoting and relapse-preventive actions on gastric ulcers.

A new screening method for anti-ulcer agents: psychological stress produced by intraspecies emotional communication.

Psychological stress produced by intraspecies emotional communication in a communication box was studied to see whether it could be applied to a new screening method for anti-ulcer agents. There were two groups of mice, the 'sender' mice that received electrical foot shocks and showed emotional responses such as piloerection, abnormal squealing and jumping, and the 'responder' mice that were affected by the sender's emotional responses without foot shock. The gastric lesions (erosions) produced by conditioned emotional stimuli were observed in both groups. The effects of the anti-ulcer drugs cetraxate, cimetidine and gefarnate were examined. In 'senders', the gastric lesions were significantly suppressed by the administration of cetraxate at a dose of 200 mg/kg (p.o.) or cimetidine at doses of 30 and 100 mg/kg (p.o.). The gastric lesions in 'responders' were significantly suppressed by two administrations of cetraxate at doses of 100 and 200 mg/kg (p.o.), cimetidine at doses of 10-100 mg/kg (p.o.) or gefarnate at a dose of 200 mg/kg (p.o.). The gastric lesions of 'responders' were more sensitive to anti-ulcer drugs. The present results indicate that the gastric erosions of 'responders' are useful for the evaluation of anti-ulcer agents.

[Effects of 3,4,5-trimethoxy-N-(3-piperidyl) benzamide (KU-54) on respiration of the gastric mucosa and liver in rats].

Effects of 3,4,5-trimethoxy-N-(3-piperidyl) benzamide (KU-54), an antiulcer drug, on the tissue respiration of the gastric mucosa and the liver were studied in rats. Oral KU-54 at 100 mg/kg twice daily for 5 days (though it was given only once on the 5th day) caused an increase in oxygen consumption of the gastric mucosa in rats, but did not affect that of the liver. Thus the principal active site of KU-54 on tissue respiration was found to be the gastric mucosa. Oral KU-54 at 100 mg/kg once daily for 11 days significantly accelerated the oxygen consumption of marginal gastric mucosa of acetic acid ulcer in rats. The effect of oral gefarnate at 200 mg/kg was about half that of KU-54 at 100 mg/kg, but it was not significant. In addition, oral KU-54 at 100 mg/kg twice daily for 5 days (though it was given only once on the 5th day) significantly inhibited the decrease of oxygen consumption of the gastric mucosa in hemorrhagic shocked rats. The effect of oral gefarnate at 100 mg/kg was not like that at KU-54 at 100 mg/kg in conscious rats. When KU-54 was added in the incubation medium with small gastric mucosal fragments of rats, the increase of oxygen consumption of the gastric mucosa did not occur. Oral KU-54 at 100 mg/kg significantly accelerated a glycogen consumptive stimulation of the gastric mucosa of the corpus in ischemic rats, but the respiration of the antral mucosa was not accelerated under anaerobic incubating conditions. Oral gefarnate at 200 mg/kg accelerated an anaerobic glycolysis of the gastric antral mucosa in rats.

Differentiation of mouse leukemic M1 cells induced by polyprenoids.

We screened several synthetic polyprenoids about their capacity of cell differentiation using mouse myeloid leukemic M1 cells, and found that 3, 7, 11, 15, 19,-pentamethyleicosa-2, 6, 10, 14, 18-pentaenol (Geranyl Farnesol) could induce the differentiation of M1 cells into macrophage-like cells. The optimal concentration of this compound for its induction capacity was approximately 2 X 10(-5) M. The induced differentiation related markers were morphological change in M1 cells, Fc receptors for IgG (Fc gamma), and non-specific esterase activity. However, phagocytic activity was poorly induced. This suggests that most of Geranyl Farnesol treated cells may be retained functionally incomplete macrophages. The presence of cycloheximide at 1 X 10(-7)M or the incubation of M1 cells at 4 degrees C completely blocked the induction of Fc gamma, suggesting the induction of Fc gamma required protein synthesis. The treatment of M1 cells with Geranyl Farnesol resulted in suppression of DNA and RNA synthesis. Further analysis of RNA metabolism suggested that the suppression of RNA synthesis was mainly due to the decrease of rRNA. On the other hand the synthesis and turnover of polyA-containing RNA (mRNA) rather increased.

Difference in mode of action of cimetidine and gefarnate on endogenous prostacyclin, prostaglandin E2 and thromboxane in rat gastric mucosa.

The effects of cimetidine and gefarnate on endogenous prostacyclin, prostaglandin E2 and thromboxane were studied in vivo in rat gastric mucosa. The animals received cimetidine (20 mg/kg, i.p.) and/or gefarnate (100 mg/kg, s.c.) twice a day for 7 days. Gastric mucosal 6-keto-prostaglandin F1 alpha (as prostacyclin), prostaglandin E2 and thromboxane B2 (as thromboxane A2) were determined by radioimmunoassay. Cimetidine reduced prostacyclin, prostaglandin E2, but not thromboxane A2. Gefarnate inhibited the cimetidine-induced reduction of prostacyclin and prostaglandin E2; in cimetidine-untreated controls, it did not produce an increase in those prostaglandins and thromboxane A2 above the normal levels.

Effect of gefarnate on endogenous prostacyclin, prostaglandin E2 and thromboxane in water-immersed rats.

The level of endogenous prostacyclin (PGI2), prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) in rat gastric mucosa was determined by radioimmunoassay to examine whether gefarnate, an antiulcer agent, maintained the endogenous prostaglandin (PG) level in rats subjected to water-immersion stress. Seven-hr immersion induced gastric lesions and a marked reduction in PGI2 and PGE2. When gefarnate was injected subcutaneously before stress exposure, the mean ulcer index was reduced and the PGI2 and PGE2 levels were maintained. Our results suggest that the reduction of endogenous PGI2 and PGE2 is a major factor in water-immersion-induced ulcers in rats, and that gefarnate inhibits this ulcer formation by inhibiting a reduction in those PGs induced by water-immersion stress.

Effects of geranylgeranylacetone on gastrointestinal secretion in rats.

The effects of geranylgeranylacetone (GGA), a new acyclic polyisoprenoid with a novel antiulcer action on gastrointestinal secretion were studied in rats. Intraduodenal administration of GGA (1-30 mg/kg) dose-relatedly reduced the gastric acid secretion caused by pentagastrin, histamine or insulin. On the other hand, GGA (3-30 mg/kg i.d.) dose-relatedly increased pancreatic secretion but did not affect biliary secretion. The above-mentioned findings seem consistent with the further findings that GGA depressed a plasma gastrin level enhanced by insulin while in increased the basal level of plasma secretin. These pharmacological features found in the present studies may partially, at least, account for the mechanism of GGA antiulcer action.

Review: effect of anti-ulcer drugs on gastric mucous barrier and possible cyclic AMP involvement.

Since cimetidine in spite of its ulcer-healing properties was found to have a damaging effect on gastric mucus, the problem of the influence of anti-ulcer drugs on mucous barrier became of topical interest. The effects of various anti-ulcer drugs on gastric mucus secretion are briefly reviewed and the possible role of changes in cyclic AMP levels of gastric mucosa is discussed.