Prevention and treatment effect of evogliptin on hepatic steatosis in high-fat-fed animal models.

Dipeptidyl peptidase 4 (DPP4) is an adipokine that interrupts insulin signaling. The resulting insulin resistance exacerbates hepatic steatosis. We previously reported that the novel DPP4 inhibitor evogliptin improves insulin resistance. This study aimed to verify the therapeutic potential of evogliptin for fatty liver. Evogliptin treatment was initiated simultaneously with a high-fat diet (HFD) feeding in normal mice and in a post-24 week HFD-fed rats. In a prevention study, insulin sensitivity was preserved in evogliptin-treated mice after a 16-week treatment. Overall plasma lipid levels stayed lower and hepatic lipid accumulation was drastically suppressed by evogliptin treatment. Evogliptin reduced hepatic expression of Srebf1, a key transcriptional factor for lipogenesis. Additionally, DPP4 inhibitor-treated mice showed less weight gain. In a treatment study, after evogliptin treatment for 14 weeks in pre-established HFD-fed obese rats, weight loss was marginal, while hepatic lipid accumulation and liver damage assessed by measuring plasma aminotransferase levels were completely resolved, suggesting weight loss-independent beneficial effects on fatty liver. Moreover, reduction in plasma non-esterified fatty acids supported the improvement of insulin resistance by evogliptin treatment. Conclusively, our findings suggest that evogliptin treatment ameliorates fatty liver by increasing insulin sensitivity and suppressing lipogenesis.

Enhancement of cancer specific delivery using ultrasound active bio-originated particles.

A hybrid multifunctional particle comprising of a microbbule (MB), liposome (Lipo), and an Fe ion chelated melanin nanoparticle (MNP(Fe)) was applied for ultrasound mediated cancer targeting as a theranostic agent.

Ultrasound-mediated gene and drug delivery using a microbubble-liposome particle system.

Theranostic agents present a promising clinical approach for cancer detection and treatment. We herein introduce a microbubble and liposome complex (MB-Lipo) developed for ultrasound (US) imaging and activation. The MB-Lipo particles have a hybrid structure consisting of a MB complexed with multiple Lipos. The MB components are used to generate high echo signals in US imaging, while the Lipos serve as a versatile carrier of therapeutic materials. MB-Lipo allows high contrast US imaging of tumor sites. More importantly, the application of high acoustic pressure bursts MBs, which releases therapeutic Lipos and further enhances their intracellular delivery through sonoporation effect. Both imaging and drug release could thus be achieved by a single US modality, enabling in situ treatment guided by real-time imaging. The MB-Lipo system was applied to specifically deliver anti-cancer drug and genes to tumor cells, which showed enhanced therapeutic effect. We also demonstrate the clinical potential of MB-Lipo by imaging and treating tumor in vivo.

Ejaculatory responses are inhibited by a new chemical entity, DA-8031, in preclinical rodent models of ejaculation.

OBJECTIVE: To investigate the efficacy of DA-8031, a novel compound for the treatment of premature ejaculation (PE), we performed in vivo pharmacological studies using 2 preclinical animal models, electrical stimulation of sensory branch of pudendal nerve (SBPdn) and para-chloroamphetamine (PCA)-induced ejaculation model. METHODS: First of all, in electrical stimulation of an SBPdn model, an SBPdn in the pelvic canal of the spinal cord transected from rats was identified. Then an electromyogram (EMG) of the bulbospongiosus (BS) muscle was recorded during electrical stimulation of SBPdn after single intravenous (IV) dosing of DA-8031 and its reference drug, dapoxetine. In the second model, both seminal vesicle pressure (SVP) and the EMG profile of the BS muscle were recorded in PCA-induced ejaculation animals after treated with the same dosing regimen. RESULTS: Area under the curve (AUC) of the BS muscle by EMG wave exhibited a significant reduction in the DA-8031 and dapoxetine 3 mg/kg treated groups, and maximum amplitudes were also significantly decreased in DA-8031 1, 3 mg/kg and dapoxetine 3 mg/kg dose level in the SBPdN stimulation model. Consistent with these findings, in a PCA-induced ejaculation model, SVP increase was significantly inhibited from DA-8031 0.3 mg/kg dose level, and AUC of BS muscle EMG significantly decreased in the DA-8031 1, 3 mg/kg groups. CONCLUSION: The present study implied that DA-8031 contributed to an effective co-coordinated inhibition of the expulsion phase of ejaculation by modulating BS muscle activity and the emission phase through blocking SVP rise. From these findings, DA-8031 is further expected to have clinical efficacy in human studies.

Udenafil enhances the recovery of erectile function and ameliorates the pathophysiological consequences of cavernous nerve resection.

INTRODUCTION: Radical prostatectomy is the treatment of choice for prostate cancer patients. Despite the introduction of nerve-sparing surgical techniques, its success is not entirely guaranteed and the majority of patients report compromised erectile function following surgical procedures. AIM: This study was performed to investigate the effect of repeated dosing of udenafil, a novel phosphodiesterase type 5 inhibitor, on penile hypoxia and fibrosis induced by bilateral cavernous nerve resection (BCNR) in rats. METHODS: Thirty male Sprague-Dawley rats (300-320 g) were used in this study. The animals were divided into three groups; group I consisted of sham-operated animals (N = 10), animals in group II underwent BCNR alone (N = 10), and animals in group III were orally treated with 10 mg/kg udenafil b.i.d. for 8 weeks following BCNR (N = 10). MAIN OUTCOME MEASURES: The expression of transforming growth factor-beta1, hypoxia-inducible factor-1 alpha, endothelial nitric oxide synthase, neuronal nitric oxide synthase, and endothelin B receptor in penile tissue was examined at gene level. Additionally, erectile function, measured by intracavernous pressure (ICP), and pathological changes in the corpus cavernosum were examined. RESULTS: While fibrosis, apoptosis, and the expression of TGF-beta1, HIF-1 alpha, and ET(B) were significantly increased, and the expression of eNOS and nNOS were significantly decreased in group II, compared with the sham-operated animals, repeated dosing of udenafil significantly ameliorated these changes. Erectile function was profoundly impaired in animals that underwent BCNR alone, and udenafil treatment significantly attenuated this impairment as measured by ICP. CONCLUSIONS: These results demonstrate that long-term administration of udenafil ameliorates penile hypoxia and fibrosis induced by cavernous nerve resection. This study also suggests the potential beneficial role of repeated dosing of udenafil in the recovery of erectile function in patients with neuronal erectile dysfunction.

Chronic administration of phosphodiesterase 5 inhibitor improves erectile and endothelial function in a rat model of diabetes.

This study was conducted to determine if the long-term administration of the phosphodiesterase type 5 (PDE 5) inhibitor, DA-8159, to diabetic rats can ameliorate the development of erectile dysfunction (ED) and endothelial dysfunction. After inducing diabetes with streptozotocin, DA-8159 was orally administered at a dose of 3 mg/kg or 10 mg/kg for 8 weeks. To examine the effect on erectile response, electrostimulation of the cavernous nerve with the parameters of 3 V, 5 ms, 5 Hz or 10 Hz, was performed to measure the intracavernous pressure (ICP) and mean arterial pressure (MAP). Thoracic aorta relaxation in vitro was evaluated by adding acetylcholine (Ach) cumulatively to the bathing medium. In addition, the plasma endothelin-1 (ET-1) levels were measured in order to investigate the effect of DA-8159 on endothelial dysfunction. The area under the curve (AUC) from the ICP/MAP ratio in the 10 Hz stimulation showed a significantly increased AUC after the 10 mg/kg treatment compared with the diabetic group (8891 +/- 619 vs. 6316 +/- 1016, respectively, p < 0.05). At the 5 Hz frequency, DA-8159 10 mg/kg also induced a significant increase in the AUC compared with the diabetic control. The maximum ICP/MAP ratio (%) of the 10 mg/kg treatment group was significantly higher in both the 10 Hz and 5 Hz frequency groups (p < 0.05). A treatment of 3 mg/kg tended to increase the AUC and peak ICP/MAP but was not statistically significant. The Ach EC50 value of the diabetic group was significantly higher than in the normal control (120.50 +/- 22.90 nm vs. 86.80 +/- 9.30 nm, respectively), and 10 mg/kg treatment group showed a significantly lower EC(50) value (88.38 +/- 19.7 nm). The ET-1 level was lower in groups treated with DA-8159, 3 mg/kg and 10 mg/kg treatment induced a statistical difference compared with the diabetic control (1.15 +/- 0.34 fmol/mL vs. 2.51 +/- 0.55 fmol/mL, respectively, p < 0.05). These results demonstrate that chronic administration of DA-8159 could attenuate the development of the ED in diabetes and its effect is associated with an improvement in the endothelial function.

DA-8159 reverses selective serotonin reuptake inhibitor-induced erectile dysfunction in rats.

OBJECTIVES: To assess the efficacy of the phosphodiesterase 5 inhibitor, DA-8159, in selective serotonin reuptake inhibitor (SSRI)-induced rat erectile dysfunction model by measuring intracavernous pressure (ICP). METHODS: Erectile dysfunction was induced by oral administration of either paroxetine or fluoxetine in rats. The changes in ICP and mean arterial pressure (MAP) were simultaneously recorded throughout electrostimulation of the cavernous nerve with 2 or 10 Hz after intravenous injection of DA-8159 (1 mg/kg). Statistical analysis was performed on the ICP/MAP ratio and the area under the curve of the ICP/MAP ratio. RESULTS: Although the reduction in the ICP responses after acute paroxetine or fluoxetine administration was statistically significant, the electrical stimulation of the cavernous nerve induced a statistically significant, frequency-dependent increase in the ICP/MAP ratio after DA-8159 administration. The differences in the ICP/MAP ratio and corresponding area under the curve values from the SSRI-treated group were statistically significant. CONCLUSIONS: The results of the present study have demonstrated that DA-8159 reverses the decrease in ICP induced by SSRI treatment, suggesting that DA-8159 may be a potential therapeutic agent for the treatment of erectile dysfunction associated with the use of SSRIs.

Increased susceptibility of ethanol-treated gastric mucosa to naproxen and its inhibition by DA-9601, an Artemisia asiatica extract.

AIM: To examine the effect of DA-9601, a new gastroprotective agent, on the vulnerability of ethanol-treated rat's stomach to naproxen (NAP). METHODS: Male Sprague-Dawley rats were pretreated with 1 mL of 50% ethanol twice a day for 5 d and then NAP (50 mg/kg) was administered. DA-9601 was administered 1 h before NAP. Four hours after NAP, the rats were killed to examine gross injury index (mm2), histologic change and to determine mucosal levels of malondialdehyde (MDA), prostaglandin E2 (PGE2), glutathione (GSH) and myeloperoxidase (MPO). RESULTS: Pretreatment of ethanol significantly increased NAP-induced gastric lesions, as well as an increase in MDA and MPO. On the contrary, mucosal PGE2 and GSH contents were decreased dramatically by ethanol pretreatment, which were aggravated by NAP. DA-9601 significantly reduced NAP-induced gastric injury grossly and microscopically, regardless of pretreatment with ethanol. DA-9601 preserved, or rather, increased mucosal PGE2 and GSH in NAP-treated rats (P<0.05), with reduction in mucosal MDA and MPO levels. CONCLUSION: These results suggest that repeated alcohol consumption renders gastric mucosa more susceptible to NSAIDs though, at least in part, reduction of endogenous cytoprotectants including PGE2 and GSH, and increase in MPO activation, and that DA-9601, a new gastroprotectant, can reduce the increased vulnerability of ethanol consumers to NSAIDs-induced gastric damage via the mechanism in which PGE2 and GSH are involved.

Effect of DA-8159, a selective phosphodiesterase type 5 inhibitor, on electroretinogram and retinal histology in rabbits.

DA-8159, a selective inhibitor of phosphodiesterase type 5, was developed as a new drug for erectile dysfunction. The effect of DA-8159 on the electroretinogram (ERG) and the retinal histopathology were evaluated in rabbits. The ERG was performed prior to, and 1 and 5 hr after DA-8159 (5 to 30 mg/kg) administration. The plasma concentration of DA-8159 was determined at each time point, and retinal microscopic examination was also performed. There was no statistically significant ERG change at any dose or at any time. Though the 30 Hz flicker showed a prolongation of the implicit time at 5 hr after the administration of either DA-8159 15 mg or 30 mg/kg (p<0.05), but concurrent amplitude decreases were not statistically significant. At a dose of 5 mg/kg, no test drug was detected in the blood after either 1 or 5 hr. At either 15 mg/kg or 30 mg/kg, there was a dose-dependent increase in the blood concentration after 1 hr of drug administration, which decreased with time. In light and electron microscopic examinations of the retina, there was no remarkable change at any dose. These results suggest DA-8159 has a low risk potential to the retina, but further evaluation on the visual functions in human is needed.

DA-8159 has erectile potentials much longer than the plasma half-life in a conscious rabbit model.

DA-8159 is a pyrazolopyrimidinone derivative which is a potent and selective phosphodiesterase type 5 inhibitor. The efficacy of oral DA-8159 has been demonstrated in conscious and spinalized rabbits by its enhancement of nitric oxide-induced erections. The aim of this study was to investigate the time dependency of this efficacy on its plasma concentration in rabbits. DA-8159 was given orally to normal rabbits at a dose of 10 or 30 mg/kg in order to determine its pharmacokinetic parameters. After then, to investigate the relationship between penile erectile activity and plasma half-life, a dose of 10 mg/kg DA-8159 was administered and the erectile response was examined in a time-course manner by measuring the length of the uncovered penile mucosa after the intravenous administration of sodium nitroprusside, which was administered 1, 3, 6, 8, 24 hours after administering DA-8159. DA-8159 was absorbed rapidly with a Tmax of 0.6 hours in 30 mg/kg and 1.0 hour in the 10 mg/kg group, and T1/2 of 1.23 hours in 30 mg/kg and 1.17 hours in 10 mg/kg, respectively. DA-8159 was not detected in the blood plasma 3 hours (10 mg/kg) or 6 hours (30 mg/kg) after administration. In an erection test, DA-8159 alone (10 mg/kg) induced a penile erection for approximately 2 hours but there was no significant erection thereafter. Although the DA-8159-induced penile erection disappeared, an intravenous injection of sodium nitroprusside significantly induced a penile erection for 6 hours, when the plasma drug concentration was below the detection limit and a no longer visible erection was noted. These results demonstrate that DA-8159 is absorbed and rapidly cleared in rabbits. In addition, it can enhance a sodium nitroprusside-induced penile erection even after 6 hours, which is approximately five times longer than the plasma half-life in the rabbits. These results suggest that DA-8159 may have an erectile potential for much longer than its measured half-life.

The effect of DA-8159 on corpus cavernosal smooth muscle relaxation and penile erection in diabetic rabbits.

A previous study showed that DA-8159, a potent type 5 phosphodiesterase inhibitor, enhanced the relaxation of the smooth muscles in the normal rabbit corpus cavernosum. In this study, we investigated the in vitro effects of DA-8159 on cavernosal smooth muscle relaxation and the in vivo erectogenic potential in diabetic rabbits, since erectile dysfunction is a well-known sequela of diabetes mellitus. Diabetes mellitus was induced in male New Zealand White rabbits with alloxan monohydrate. Cavernosal strips from age-matched control and 8-week diabetic animals were mounted in organ baths. The relaxation responses to sodium nitroprusside (10(-9)--10(-5) M), a nitric oxide donor, were assessed in the presence or absence of DA-8159 (10(-9)--10(-6) M). For the penile erection test, DA-8159 was given orally (1-10 mg/kg) to diabetic rabbits and the length of the uncovered penile shaft was measured in a time-course manner in the presence or absence of intravenous sodium nitroprusside. The sodium nitroprusside-stimulated relaxations were significantly impaired in the corpus cavernosum from the diabetic group (IC(50)=1.07 x 10(-6) M following 8 weeks of diabetes mellitus; compared with 0.48 x 10(-6) M for age-matched controls). DA-8159 significantly and dose-dependently enhanced the sodium nitroprusside-stimulated relaxation in the diabetic groups. In addition, DA-8159 induced a dose-dependent penile erection in diabetic rabbits, which was potentiated by intravenous sodium nitroprusside. These results suggest that DA-8159 is an effective treatment for diabetic erectile dysfunction but further evaluation of the efficacy on human needs to be performed.

DA-8159, a potent cGMP phosphodiesterase inhibitor, attenuates monocrotaline-induced pulmonary hypertension in rats.

In this study, we evaluated the effects of oral administration of DA-8159, a selective phosphodiesterase-5 inhibitor, on the development of pulmonary hypertension (PH) induced by monocrotaline (MCT). Rats were administered either MCT (60 mg/kg) or saline. MCT-treated rats were divided into three groups and received orally administered vehicle, or 1 mg/kg or 5 mg/kg of DA-8159, twice a day for twenty-one days. The MCT group demonstrated increased right ventricular weights, medial wall thickening in the pulmonary arteries, myocardial fibrosis and the level of plasma cyclic guanosine monophosphate (cGMP), along with decreased body weight gains. However, DA-8159 markedly and dose-dependently reduced the development of right ventricular hypertrophy and medial wall thickening. DA-8159 also amplified the increase in plasma cGMP level and significantly increased the level of lung cGMP, compared with the MCT group. Although the body weight gain was still lower from the saline-treated control group, DA-8159 demonstrated a significant increase in body weight gains, in both 1 mg/kg and 5 mg/kg groups, when compared with the MCT group. In myocardial morphology, MCT-induced myocardial fibrosis was markedly prevented by DA-8159. These results suggest that DA-8159 may be a useful oral treatment option for PH.

DA-8159, a new PDE5 Iihibitor, induces penile erection in conscious and acute spinal cord injured rabbits.

OBJECTIVES: DA-8159 is a pyrazolopyrimidinone derivative showing potent and selective phosphodiesterase 5 (PDE5) inhibition. In the previous study, DA-8159 induced a dose-dependent increase in the intracavernous pressure (ICP) in anaesthetized dogs. The aim of this study was to investigate the effects of DA-8159 on penile erection in conscious and acute spinal cord injured (ASCI) rabbits. METHODS: DA-8159 was given orally (0.3 to 10mg/kg) to normal rabbits and ASCI rabbits with a surgical transection of the spinal cord at the L2-L4 lumbar vertebra or ischemic-reperfusion. The erection was evaluated in a time-course manner by measuring the length of the uncovered penile mucosa in the absence or presence of intravenous sodium nitroprusside (SNP), a nitric oxide (NO) donor. RESULTS: DA-8159 induced a dose-dependent penile erection in both the conscious and ASCI rabbits. The efficacy of DA-8159 was potentiated and the effective doses were significantly decreased by an intravenous injection of SNP. Potentiation of the effect by a nitric oxide donor implies that DA-8159 can enhance the erectile activity during sexual arousal. CONCLUSION: These results demonstrate that DA-8159 may be a useful treatment option for erectile dysfunction in patients with or without a spinal cord injury, but further evaluation of the effects of DA-8159 on humans must be performed.