Daily application of alprostadil topical cream (Vitaros) does not impact vaginal pH, flora, or histology in female cynomolgus monkeys.

Topical alprostadil cream (Vitaros) is approved in Canada and Europe for the treatment of erectile dysfunction. To determine the effects on the female urogenital tract with repeated administration of the entire dose (300 µg alprostadil containing 2.5% dodecyl-2-n,n-dimethylaminopropionate hydrochloride), the vaginal pH, flora, and histology were assessed as a model for 100% transference from male to the female during unprotected sexual intercourse. Female cynomolgus monkeys were administered the entire dose of Vitaros for 14 days with a 7-day recovery. Relative to vehicle and placebo cream, the vaginal pH and microflora were determined at baseline and weekly, thereafter. Vaginal biopsies were evaluated at the end of dosing and recovery. All animals were clinically normal for the study duration, and the vaginal pH was consistent between dose groups and the dosing period. Vaginal microflora and histopathology findings of mild inflammation were generally similar across treatment groups. In conclusion, repeated vaginal exposure to Vitaros did not alter the pH, microflora, or histology after 14 daily doses, supporting the safety of Vitaros transference to the female partner.

Toxicity of prolonged high dose inhaled PGE1 in ventilated neonatal pigs.

OBJECTIVE: To study the toxicity of inhaled PGE1 (IPGE1) in healthy ventilated piglets. METHODS: Mechanically ventilated anesthetized piglets received either high dose IPGE1 (IPGE1 group) or nebulized saline (control group) continuously for 24h. Cardio-respiratory parameters, complete blood counts and serum electrolytes were monitored. Lung histology was evaluated by a masked pathologist for the severity (minimal, moderate, and severe) and extent (focal, multifocal, and diffuse) of histologic injury. RESULTS: Ten neonatal pigs were instrumented. Four received nebulized saline and six received high dose IPGE1. There was no evidence of adverse cardio-respiratory effects, bronchial irritation or hypernatremia related to IPGE1. Diffuse/multifocal alveolar edema and focal polymorphonuclear infiltration was observed in both the control and IPGE1 groups suggesting that alveolar alterations may be secondary to effects of mechanical ventilation. The most distinct histomorphological abnormalities observed in the IPGE1 animals were focal ulceration, flattening of the bronchial epithelium and loss of cilia of moderate to severe degree in the trachea and bronchi. CONCLUSION: In healthy piglets, inhalation of high dose IPGE1 was not associated with adverse cardiorespiratory effects, bronchial irritation, or hypernatremia and produced minimal signs of pulmonary toxicity even after 24h. Prolonged inhalation of high dose PGE1 therefore appears safe in newborn piglets.

Cytotoxicity of different intracavernous vasoactive drugs on cultured endothelial cells of human corpus cavernosum penis.

OBJECTIVES: To investigate the cytotoxic effect of prostaglandin E(1) (PGE(1)), a standard combination of papaverine/phentolamine, and a triple mixture of these agents on human cavernosal endothelial cells using a cell culture model. The endothelial layer of the corpus cavernosum plays an important role in signal transduction of penile erection and is directly exposed to vasoactive agents after intracavernous injection for erectile dysfunction. METHODS: Primary endothelial cells were obtained from the corpus cavernosum of 13 potent patients undergoing penile surgery. Cultured cells were exposed for 30 minutes to physiologic dilutions of 20 microg PGE(1), 30 mg papaverine/1 mg phentolamine, or the same dosages of the triple mixture of these agents, each dissolved in 5 to 50 mL sodium chloride. Lactate dehydrogenase release as a cytotoxicity marker was measured 6 hours after drug exposure, and the total cell metabolic activity was quantified after 48 hours with a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS)-based assay. Additionally, the amount of viable cells was identified with a dual fluorescent staining procedure. RESULTS: The initial release of lactate dehydrogenase was elevated up to 3.2-fold in the concentrated papaverine/phentolamine and triple mixture group compared with PGE(1) and the control. After 48 hours, the papaverine-containing formulations led to a significant dose-dependent decrease in the viable cell count and metabolic activity of the cultures that was not noticed with PGE(1). CONCLUSIONS: These in vitro data strongly suggest an unfavorable effect of vasoactive agents containing papaverine on cavernosal endothelial cells. Before fibrotic changes of the smooth muscle stroma, the functionally important endothelium of the corpus cavernosum might suffer significantly from intracavernous injection therapy. Therefore, papaverine should no longer be used for this indication.

Short-term histopathologic effects of different intracavernosal agents on corpus cavernosum and antifibrotic activity of intracavernosal verapamil: an experimental study.

OBJECTIVES: To evaluate the short-term effects of different intracavernosal agents and to investigate the antifibrotic effect of verapamil combined with these intracavernosal agents. METHODS: Forty-five Sprague-Dawley rats weighing 400 to 500 g each (mean weight 435.27 +/- 13.65 g) were equally divided into nine groups (n = 5). Papaverine (group 1), alprostadil (group 2), sodium nitroprusside (group 3), and verapamil (group 4) were injected alone intracavernously in 0.2-mL doses. Verapamil combined with papaverine, alprostadil, and sodium nitroprusside in 0.2-mL doses (0.1 mL verapamil and 0.1 mL vasoactive agent) were injected in groups 5 through 7. Group 8 was kept as a control group without injection, and isotonic saline alone was injected in group 9 during the same period. The intracavernous injection was done twice weekly with a 4-day interval. At the end of the study, total penectomy and multiple liver biopsies were performed to evaluate the histopathologic effects of the vasoactive agents and to test the liver function. RESULTS: In all groups, the structure of the corpora cavernosa was well preserved generally and appeared similar to the control tissue. However, localized edema, fibrosis, macrophage infiltration, and polymorphonuclear leukocytes were found only at the injection site. Although these findings were not different from the findings in the saline and alprostadil groups, they were slightly more extensive in the papaverine and sodium nitroprusside alone groups and also in the vasoactive agent plus verapamil groups. Although mononuclear lymphocyte infiltration was found in the portal areas, advancing into the liver parenchyma, the liver function tests were within normal limits. CONCLUSIONS: We observed that intracavernous injection, except with nitroprusside, caused focal intracavernosal fibrosis and edema. We believe these effects might not be caused by just the drug, but also by needle trauma, since general fibrosis was not observed in the short term. However, nitroprusside has a severe fibrotic effect on cavernosal tissue in the short term. Moreover, intracavernous verapamil injection could not prevent the fibrosis in the short term.

Effects of tetramethylpyrazine on prostaglandin E(2)- and prostaglandin E(2) receptor agonist-induced disruption of blood-aqueous barrier in pigmented rabbits.

PURPOSE: To evaluate the effect of tetramethylpyrazine on the elevation of aqueous flare and intraocular pressure (IOP) induced by prostaglandin (PG) E(2) and PGE(2) receptor (EP) agonists. METHODS: PGE(2) or EP agonists (11-deoxy PGE(1), EP(2) agonist; 17-phenyl trinor PGE(2), EP(1) and EP(3) agonist; or sulprostone, EP(1) and EP(3) agonist), 25 microg/mL, were transcorneally administered to pigmented rabbits. Animals were pretreated with tetramethylpyrazine intravenously (10 or 30 mg/kg) or topically (0.1% solution). Aqueous flare was measured using a laser flare-cell meter, and the intensity was expressed as the area under the curve (AUC). Intraocular pressure was measured using a noncontact tonometer. RESULTS: After administration of PGE(2), aqueous flare and IOP increased and then gradually decreased. The AUC of eyes pretreated with tetramethylpyrazine, 10 or 30 mg/kg, intravenously, or topical 0.1% solution, was significantly smaller than that of the controls. The mean Delta IOP of eyes pretreated with tetramethylpyrazine, 30 mg/kg intravenously, was significantly lower than that of the controls. After administration of 11-deoxy PGE(1), aqueous flare increased and then gradually decreased. 17-phenyl trinor PGE(2) and sulprostone did not disrupt the blood-aqueous barrier. The AUC of eyes pretreated with tetramethylpyrazine, 10 or 30 mg/kg, intravenously, before 11-deoxy PGE(1) application was significantly smaller than that of the controls. CONCLUSION: The results indicated that tetramethylpyrazine inhibited PGE(2)- or 11-deoxy PGE(1)-induced elevation of aqueous flare and IOP.

Prostaglandins act as neurotoxin for differentiated neuroblastoma cells in culture and increase levels of ubiquitin and beta-amyloid.

Although chronic inflammatory reactions have been proposed to cause neuronal degeneration associated with Alzheimer's disease (AD), the role of prostaglandins (PGs), one of the secretory products of inflammatory reactions, in degeneration of nerve cells has not been studied. Our initial observation that PGE1-induced differentiated neuroblastoma (NB) cells degenerate in vitro more rapidly than those induced by RO20-1724, an inhibitor of cyclic nucleotide phosphodiesterase, has led us to postulate that PGs act as a neurotoxin. This study has further investigated the effects of PGs on differentiated NB cells in culture. Results showed that PGA1 was more effective than PGE1 in causing degeneration of differentiated NB cells as shown by the cytoplasmic vacuolation and fragmentation of soma, nuclei, and neurites. Because increased levels of ubiquitin and beta-amyloid have been implicated in causing neuronal degeneration, we studied the effects of PGs on the levels of these proteins during degeneration of NB cells in vitro by an immunostaining technique, using primary antibodies to ubiquitin and beta-amyloid. Results showed that PGs increased the intracellular levels of ubiquitin and beta-amyloid prior to degeneration, whereas the degenerated NB cells had negligible levels of these proteins. These data suggest that PGs act as external neurotoxic signals which increase levels of ubiquitin and beta-amyloid that represent one of the intracellular signals for initiating degeneration of nerve cells.

Aspartic and glutamic acids increase in the frontal cortex during prostaglandin E1 hyperthermia.

The aim of the present experiment was to evaluate the role played by aspartic acid and glutamic acid of frontal cerebral cortex during the hyperthermia induced by prostaglandin E1. Two groups of six Sprague Dawley male rats were anaesthetized with ethyl-urethane. The frontal cortical concentrations of aspartic and glutamic acids, the firing rate of the sympathetic nerves to the interscapular brown adipose tissue, the colonic and interscapular brown adipose tissue temperatures were monitored both before and after an intracerebroventricular injection of prostaglandin E1 (500 ng) or saline. Aspartic and glutamic acids were collected using a microdialysis probe placed in the frontal cortex. Concentrations of aspartic and glutamic acids were measured by high-pressure liquid chromatography with fluorescence detector. Prostaglandin E1 induced an increase in the concentrations of aspartic and glutamic acids, in the firing rate of sympathetic nerves and in the colonic and interscapular brown adipose tissue temperatures. The findings of the present experiment indicate that an intracerebroventricular injection of prostaglandin E1 causes release of aspartic and glutamic acids in the frontal cortex.

Comparison of prostaglandin E1- and prostaglandin E2-induced hyperalgesia in the rat.

We have studied prostaglandin E1-induced mechanical hyperalgesia in the rat hindpaw, by assessing paw-withdrawal thresholds, before and after injecting prostaglandin E1 alone or with other agents, in normal and streptozotocin-induced diabetic rats. In normal and diabetic rats, prostaglandin E1 (1-1000 ng) produced a dose-dependent decrease in mechanical nociceptive threshold. In diabetic rats, prostaglandin E1 was more potent than in normal rats, in producing hyperalgesia, whereas prostaglandin E2 hyperalgesia was not changed in normal and diabetic rats. Prostaglandin E1-induced hyperalgesia was not inhibited by E-type 1 prostaglandin receptor antagonists, SC19220 or SC51089, either in normal or diabetic rats. In fact, in the presence of SC19220, prostaglandin E1 produced enhanced hyperalgesia, in normal rats. Prostaglandin E1 hyperalgesia was not significantly modified by sympathectomy or indomethacin. Unlike prostaglandin E2, prostaglandin E1 hyperalgesia was not blocked by the inhibitor of the stimulatory guanine nucleotide-binding regulatory protein, guanosine 5'-O-(2-thiodiphosphate). It is suggested that prostaglandin E1 decreases primary afferent nociceptive threshold directly, by activating a prostaglandin receptor other than the E-type 1 prostaglandin receptor, and that this receptor is not coupled to a stimulatory guanine nucleotide-binding regulatory protein.

Improvement of gingival and alveolar bone status in periodontitis-affected hamsters treated with 15-methyl prostaglandin E1.

Exogenous PGE1 at pharmacological doses suppresses acute and chronic inflammation manifestations. As periodontitis possesses features of both acute and chronic inflammation, attenuation of periodontal destruction in hamsters was attempted by using 15-M-PGE1, a stable PGE1 analog. The agent was tested at 2 different doses (100 and 150 micrograms/kg/d) and its effects were matched against disease-free and periodontitis-affected animals. No effect was found with the 100 micrograms regimen. In contrast, in the 150 micrograms group, in the gingiva around the first right mandibular molar the pocket epithelium and infiltrated connective tissue (ICT) areas, the mean vascular lumen, the number of PMNLs adherent to blood vessels and infiltrating the ICT were significantly reduced. The number of osteoclasts was markedly diminished as well, but their intrinsic activity was enhanced. Bone formation was totally inhibited in this treatment group. These results indicated that 15-M-PGE1 effectively improved gingival inflammation mostly by reducing edema and PMNL recruitment and controlled alveolar bone destruction by reducing the osteoclast recruitment. From a therapeutic point of view the complete inhibition of formation seems to contraindicate its use.

[Effects of hypotensive anesthesia with prostaglandin E1 or trimethaphan on renal microstructure].

A study was made on the presence or absence and the degree of histopathological renal cell damage, in hypotensive anesthesia models with prostaglandin E1 (PGE1) or trimethaphan. Cell damage was most noticeable in the S3 segment, the straight and second half part of the proximal renal tubule. The lesion was evaluated and semiquantified. The trimethaphan group in this area exhibited degeneration--including cell vacuolation and granule increase in this site, as well as cytoclasis such as cell fragments in the lumen, luminal extension, flattening of epithelial cell and damage of distal renal tubular columns. In the PGE1 group, cell degeneration was milder than in the trimethaphan group, and there were no cytoclasis findings. Renal cell damage in the PGE1 group was slighter than in the trimethaphan group.

Biological activity of prostaglandin E3 with regard to oedema formation in mice.

The biological activity of PGE3 with regard to oedema formation in mice was examined. Paw swelling was measured 30 minutes after injection of 10 microliters PGE2 or PGE3 into the plantar region of the hind paw. Doses investigated ranged from 1 ng-10 micrograms. Both PGE2 and PGE3 had substantial oedemogenic activity in this system.

[The luteotropic and luteolytic properties of synthetic analogs of 11-deoxy-PGE1]. / Liuteotropnye i liuteoliticheskie svoistva sinteticheskikh analogov 11-dezoksi-PGE1.

The luteotropic and luteolytic properties of synthetic analogues of 11-desoxy-PGE1 were studied. Compounds Nos. 1 and 2 depending on the dose exerted the opposite effect: in low doses--luteotropic, in high doses--luteolytic. Compounds Nos. 3, 4 and 5 in the whole range of doses exhibited only luteolytic properties. The ranges of doses of prostaglandin exerting the luteotropic effect depend on the structural modifications of prostaglandin molecule. The luteolytic effect of synthetic analogue No. 5 was suggested to be determined by its influence on the hypophysis through the change of contents of cyclic nucleotides and gonadotropic hormones. It was demonstrated that the luteolytic effect of compound No. 5 is realized through the central nervous system, in particular, through the hypophysis.

A new prostaglandin E1 analogue (TFC-612) improves the reduction in motor nerve conduction velocity in spontaneously diabetic GK (Goto-Kakizaki) rats.

A new prostaglandin E1 analogue, TFC-612, was given orally to 2 month-old spontaneously diabetic GK (Goto-Kakizaki) rats for 3 months to ascertain its effects on reduced motor nerve conduction velocity (MCV). A high dose of this compound (0.3 mg/kg body weight) significantly restored MCV after 2 and 3 months of administration, although the low dose (0.03 mg/kg body weight) did not. In addition, 1 month administration of TFC-612 significantly improved the reduced MCV in aged (5 month-old) GK rats only in the high dose group (0.3 mg/kg body weight), but not in the low dose group (0.03 mg/kg body weight). Although TFC-612 significantly suppressed sorbitol accumulation in the sciatic nerves of GK rats in a dose dependent manner after 3 months administration, this suppression was not observed after either 2 months administration to 2 month-old GK rats or after 1 month administration to 5 month-old GK rats. Fasting blood glucose levels of all GK rats remained high throughout the experiments, regardless of TFC-612 administration. TFC-612's improvement on reduced motor nerve conduction velocity was related partly to suppression of sorbitol accumulation, but other factors, including microcirculation, may contribute significantly to this effect. These results suggest that TFC-612 may be beneficial in the treatment of diabetic nerve impairment.

[Effect of 11-deoxyprostaglandins E on the reproductive system]. / Vliianie 11-dezoksi-prostaglandinov E na reproduktivnuiu sistemu.

The pharmacological properties of 4 derivatives of 11-desoxy-prostaglandins E (uterotonic, luteolytic, hypotensive, anti-inflammatory, diarrhogenic ones and also acute toxicity) were studied. Compound I possessed the uterotonic activity which decreased with an alpha-chain elongation and a radical introduction into a benzene ring. Compounds I and II exhibited the luteotropic properties at low doses and the luteolytic ones at high doses. The compounds under study had the hypotensive activity due to the presence of a benzene ring in a W-chain.

Prostaglandin E1-associated pathology of pulmonary microvasculature in newborn pups: similarity to findings in prostaglandin E1-treated human newborns.

Prostaglandin E1 (PGE1) administration is a useful therapeutic measure for short-term maintenance of ductal patency in patients with obstructions to pulmonary or systemic blood flow. Such treatment is not without complications, however, and a report of three infants from our institution with abnormalities of the pulmonary microvasculature after varying periods of PGE1 therapy was recently published (Heffelfinger et al., Pediatr Pathol 1987;7:165-73). The vascular abnormalities appeared to be temporally related to the PGE1 administration. To test this hypothesis, we investigated the effects of PGE1 in newborn beagles by infusing PGE1 for periods of up to 21 days in four experimental pups. Two control pups were infused with saline for the same period of time. Five of the animals developed respiratory infection during the course of the infusions. One PGE1-treated pup was not infected. Both the PGE1- and saline-treated pups had bronchopneumonias of similar severity; however, pulmonary arteritis occurred only in the PGE1-treated pups. The severity of the arteritis varied with the amount of pulmonary parenchymal inflammation and not with the duration of PGE1 administration. Inflammatory and vascular lesions were found in organs other than the lung only in two pups receiving longer courses of PGE1 treatment. We conclude that systemic PGE1 infusion at therapeutic levels plays a role in the development of arterial lesions in small muscular arteries and that this is potentiated by the presence of infection.

Adverse effects of (15S)-15-methyl-prostaglandin E1 in normal and paraquat-exposed rats.

Single, daily injections of approximately 1 mg/kg of (15S)-15-methyl-PGE1 (mPGE1), a PGE1 analog, have been reported to inhibit inflammation and to prolong survival in several animal models of local and systemic inflammation. We examined the effect of this dose of mPGE1 on paraquat toxicity in rats. A significant increase in early mortality was identified in mPGE1-treated rats as early as 3 hr following injection of paraquat and appeared associated with increased respiratory effort. Rats given mPGE1 without paraquat also appeared to increase respiratory effort but did not die. Rats killed at 3 hr following injections demonstrated increased lung weights in both paraquat-injected and control animals receiving mPGE1. Although a neutrophilia was identified in these animals, no significant increase in lung lavage neutrophils or albumin was identified. These data suggest that large intermittent doses of a PGE1 analog may adversely affect the respiratory system of normal and injured animals, and will accelerate mortality following exposure to potentially lethal doses of paraquat.

Effect of chronic misoprostol ingestion on rat gastric morphology and cell turnover.

The effect of long-term misoprostol - a synthetic prostaglandin E1 analogue - ingestion on rat gastric morphology and cell turnover was studied. Misoprostol in a daily dose of 90 micrograms/kg or 9,000 micrograms/kg was intragastrically administered to rats. Control rats were treated with the vehicle only. Following 90 days of treatment, 3H thymidine was injected i.v. and rats were sacrificed 1 h later. Tissue sections were prepared from the stomach body and subjected to autoradiography. Misoprostol treatment significantly reduced body weight gain. High dose misoprostol treatment induced significant increases in gastric wall thickness and in gastric gland length. On the other hand, the labelling index was significantly reduced by treatment with high dose misoprostol. These results indicate that chronic administration of misoprostol in high doses increases gastric wall thickness and decreases gastric cell turnover, suggesting that administration of prostanoids causes an increase in cell survival and a decrease in cell shedding.