Expression Of Phosphodiesterase Research Articles

Phosphodiesterase 5 (PDE5) Is Highly Expressed in Cancer-Associated Fibroblasts and Enhances Breast Tumor Progression.

The overexpression of phosphodiesterase (PDE) 5 is frequently found in various human cancers, such as those of the breast. However, PDE5’s role in the tumor microenvironment is still unknown. As PDE5 represents a high-value therapeutic target, we investigated whether the expression and function of PDE5 in breast cancer-associated fibroblasts (CAFs) may be clinically relevant to malignant progression. PDE5 expression was increased in human breast cancer stroma compared with normal stroma and was correlated to a shorter overall survival. Treatment of CAFs, isolated from breast tumor biopsies, with selective PDE5 inhibitors inhibited their proliferation, motility, and invasiveness, and negatively controlled tumor–stroma interactions in both ‘in vitro’ and ‘in vivo’ models. PDE5 stable overexpression transformed immortalized mouse embryonic fibroblasts (MEFs) towards an activated fibroblast phenotype, impacting their intrinsic characteristics and paracrine effects on breast cancer cell growth and migration through an enhanced production of the C-X-C motif chemokine 16 (CXCL16). On the other hand, CAF exposure to PDE5 inhibitors was associated with reduced CXCL16 expression and secretion. Importantly, CXCL16 levels in breast cancer stroma showed a strong correlation with PDE5 levels and poor patient outcomes. In conclusion, PDE5 is overexpressed in breast cancer stroma, enhances the tumor-stimulatory activities of fibroblasts, and impacts clinical outcomes; thus, we propose this enzyme as an attractive candidate for prognosis and a potential target for treatments in breast cancer patients.

The Neuroprotective Effect of Amitriptyline on Radiation-Induced Impairment of Hippocampal Neurogenesis.

The radioprotective effect of amitriptyline, an inhibitor of acid sphingomyelinase (ASMase), on radiation-induced impairment of hippocampal neurogenesis, loss of interneuron, and animal weight changes was investigated in BALB/c mice by immunostaining of biomarkers for cell division (Ki67), immature neurons (doublecortin or DCX), and interneurons (parvalbumin or PV) in the dentate gyrus (DG) of hippocampus. The results indicated that preirradiation (with 10 mg/kg, 2 times per day, for 7 consecutive days) or postirradiation (with 10 mg/kg, 2 times per day, for 14 consecutive days) treatment (pretreatment or posttreatment) with intraperitoneal injection of amitriptyline prevented the loss of newly generated neurons, proliferating cells, and interneurons in the subgranular zone of the DG. At the molecular level, pretreatment or posttreatment inhibited the expression of sphingomyelin phosphodiesterase 1 (SMPD1) gene which codes for ASMase. The pretreatment for 7 days also prevented radiation-induced weight loss from 2 to 3 weeks, but not within 1 week after irradiation. On the other hand, the posttreatment with amitriptyline for 14 days could improve animal weight gain from 4 to 6 weeks after irradiation. The present study suggests that amitriptyline may be a promising candidate radio-neuroprotective drug to improve radiation-induced impairment of hippocampal neurogenesis and relevant neurological and neuropsychological disorders.

Mitochondrial sub-cellular localization of cAMP-specific phosphodiesterase 8A in ovarian follicular cells

Cyclic adenosine monophosphate (cAMP) is a ubiquitous secondary messenger that plays a central role in endocrine tissue function, particularly in the synthesis of steroid hormones. The intracellular concentration of cAMP is regulated through its synthesis by cyclases and its degradation by cyclic nucleotide phosphodiesterases (PDEs). Although the expression and activity of PDEs impact the specificity and the amplitude of the cAMP response, it is becoming increasingly clear that the sub-cellular localization of PDE emphasizes the spatial regulation of the cell signalling processes that are essential for normal cellular function. We first examined the expression of PDE8A in porcine ovarian cells. PDE8A is expressed in granulosa cells, cumulus cells and oocytes. Second, we assessed the mitochondrial sub-cellular localization of PDE8A. Using western blotting with isolated mitochondrial fractions from granulosa cells and cumulus-oocyte complexes revealed immuno-reactive bands. PDE assay of isolated mitochondrial fractions from granulosa cells measured specific PDE8 cAMP-PDE activity as PF-04957325-sensitive. The immune-reactive PDE8A signal and MitoTracker labelling co-localized supporting mitochondrial sub-cellular localization of PDE8A, which was confirmed using immuno-electron microscopy. Finally, the effect of PDE8 on progesterone production was assessed during the in-vitro maturation of cumulus-oocyte complexes. Using PF-04957325, we observed a significant increase (P < 0.05) in progesterone secretion with follicle-stimulating hormone (FSH). Active mitochondria stained with MitoTracker orange CMTMRos were also increased by the specific PDE8 inhibitor supporting its functional regulation. In conclusion, we propose the occurrence of mitochondrial sub-cellular localization of PDE8A in porcine granulosa cells and cumulus cells. This suggests that there is potential for new strategies for ovarian stimulation and artificial reproductive technologies, as well as the possibility for using new media to improve the quality of oocytes.

Regulation of PDE5 expression in normal prostate, benign prostatic hyperplasia, and adenocarcinoma.

Type 5 phosphodiesterase (PDE5) expression in the normal and pathological prostate is controversial. This study aimed at identifying the cell type/s, if any, expressing PDE5 in human healthy or pathological prostate sections in order to further validate the rationale of PDE5 inhibitor (PDE5i) treatment of benign prostatic hyperplasia (BPH) and their safety in the treatment of erectile dysfunction following prostate cancer (PCa) surgery. By immunohistochemical analysis, we studied PDE5 expression in tissue microarrays containing sections obtained from healthy, BPH, and PCa samples. Our results showed that PDE5 is barely expressed in the epithelial or stromal compartment of normal human prostates, but it is highly expressed in the stromal compartment of BPH sections. We also found that a low but significant number of PCa samples (22%) expressed PDE5 in the epithelial cancer cells but not in stromal cells and that such expression was not correlated with the tumor aggressiveness, according to their Gleason score. PDE5 overexpression in the stromal compartment of BPH samples supports the rationale of PDE5 as a target in lower urinary tract symptoms of BPH. PDE5 expression in a significant percentage of PCa samples but the lack of correlation with the Gleason score suggests that this enzyme is not correlated with tumor aggressiveness; however, a role of PDE5 in the minimal residual disease of PCa cannot be excluded.

Changes of the Expression and Activity of Phosphodiesterase V in the Basilar Artery Before and After Cerebral Vasospasm in a Rabbit Model

To examine changes of expression and activity of phosphodiesterase V (PDE V) in the basilar artery following cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) in a rabbit model. A rabbit model of CVS after SAH was constructed by double blood injection into the cisterna magna. Subjects were divided into 3 groups: blank control group, normal saline group, and SAH group. Transcranial Doppler and selective vertebrobasilar digital subtraction angiography were performed to identify changes of CVS. Changes of PDE V expression and activity were examined. Mean basilar arterial blood flow rate measured by transcranial Doppler was significantly increased in the SAH group compared with the blank control group and normal saline group. Mean basilar artery diameter measured by digital subtraction angiography in the SAH group was narrower than in the other 2 groups. Compared with the other 2 groups, the expression of PDE V in the SAH group was significantly upregulated, and the activity was significantly enhanced. The rabbit model of SAH-induced CVS was successfully constructed through double blood injection method. Increased basilar artery blood flow, narrowing of the basilar artery, increased PDE V expression, and enhanced PDE V activity in the basilar artery were detected in the CVS rabbits, suggesting that PDE V has the potential to be used as a target for CVS therapy.

Hydroalcoholic Extract of Levisticum officinale Increases cGMP Signaling Pathway by Down-Regulating PDE5 Expression and Induction of Apoptosis in MCF-7 and MDA-MB-468 Breast Cancer Cell Lines

This study aimed to investigate Levisticum officinale hydroalcoholic extract (LOHE) effect on both cGMP signaling pathway and phosphodiesterase 5 (PDE5) gene expression pattern and to examine the role of LOHE in apoptosis induction of MCF-7 and MDA-MB-468 cell lines. The half maximal inhibitory concentration (IC50) of LOHE was examined in both cell lines using the MTT assay. Using IC50 values of LOHE on both cells, the type of cell death was detected by flowcytometric analysis. The values of PDE5 and cGMP were evaluated by real-time PCR and ELISA methods, respectively. The IC50 values were measured as 150 μg/ml for MDA-MB-468 and 200 μg/ml for MCF-7. At 12 hour of treatment, a significant decrease in the PDE5 expression and maximum increase in the amount of intracellular cGMP were observed (p < 0.05). However, these effects were more noticeable in MDA-MB-468 triple-negative cells. Our data suggest that LOHE extract could be a potential source for new strategies towards targeting both PDE5 and cGMP signaling pathways.

Hydroalcoholic Extract of Levisticum officinale Increases cGMP Signaling Pathway by Down-Regulating PDE5 Expression and Induction of Apoptosis in MCF-7 and MDA-MB-468 Breast Cancer Cell Lines

Background:This study aimed to investigate Levisticum officinale hydroalcoholic extract (LOHE) effect on both cGMP signaling pathway and phosphodiesterase 5 (PDE5) gene expression pattern and to examine the role of LOHE in apoptosis induction of MCF-7 and MDA-MB-468 cell lines.Methods:The half maximal inhibitory concentration (IC50) of LOHE was examined in both cell lines using the MTT assay. Using IC50 values of LOHE on both cells, the type of cell death was detected by flowcytometric analysis. The values of PDE5 and cGMP were evaluated by real-time PCR and ELISA methods, respectively.Results:The IC50 values were measured as 150 μg/ml for MDA-MB-468 and 200 μg/ml for MCF-7. At 12 hour of treatment, a significant decrease in the PDE5 expression and maximum increase in the amount of intracellular cGMP were observed (p < 0.05). However, these effects were more noticeable in MDA-MB-468 triple-negative cells.Conclusion:Our data suggest that LOHE extract could be a potential source for new strategies towards targeting both PDE5 and cGMP signaling pathways.

Pistacia weinmannifolia ameliorates cigarette smoke and lipopolysaccharide‑induced pulmonary inflammation by inhibiting interleukin‑8 production and NF‑κB activation.

Pistacia weinmannifolia (PW) has been used in traditional Chinese medicine to treat headaches, dysentery, enteritis and influenza. However, PW has not been known for treating respiratory inflammatory diseases, including chronic obstructive pulmonary disease (COPD). The present in vitro analysis confirmed that PW root extract (PWRE) exerts anti-inflammatory effects in phorbol myristate acetate- or tumor necrosis factor α (TNF-α)-stimulated human lung epithelial NCI-H292 cells by attenuating the expression of interleukin (IL)-8, IL-6 and Mucin A5 (MUC5AC), which are closely associated with the pulmonary inflammatory response in the pathogenesis of COPD. Thus, the aim of the present study was to evaluate the protective effect of PWRE on pulmonary inflammation induced by cigarette smoke (CS) and lipopoly-saccharide (LPS). Treatment with PWRE significantly reduced the quantity of neutrophils and the levels of inflammatory molecules and toxic molecules, including tumor TNF-α, IL-6, IL-8, monocyte chemoattractant protein-1, neutrophil elastase and reactive oxygen species, in the bronchoalveolar lavage fluid of mice with CS- and LPS-induced pulmonary inflammation. PWRE also attenuated the influx of inflammatory cells in the lung tissues. Furthermore, PWRE downregulated the activation of nuclear factor-κB and the expression of phosphodiesterase 4 in the lung tissues. Therefore, these findings suggest that PWRE may be a valuable adjuvant treatment for COPD.

Corrigendum to: “Characterization of Sphingomyelin Phosphodiesterase Expression in Bumblebee (Bombus lantschouensis)”

Corrigendum to: “Characterization of Sphingomyelin Phosphodiesterase Expression in Bumblebee (Bombus lantschouensis)”

Understanding the pathobiology in patent ductus arteriosus in prematurity-beyond prostaglandins and oxygen.

The ductus arteriosus (DA) is probably the most intriguing vessel in postnatal hemodynamic transition. DA patency in utero is an active state, in which prostaglandin E2 (PGE2) and nitric monoxide (NO), play an important role. Since the DA gets programmed for postnatal closure as gestation advances, in preterm infants the DA frequently remains patent (PDA). PGE2 exposure programs functional postnatal closure by inducing gene expression of ion channels and phosphodiesterases and anatomical closure by inducing intimal thickening. Postnatally, oxygen inhibits potassium and activates calcium channels, which ultimately leads to a rise in intracellular calcium concentration consequently inducing phosphorylation of the myosin light chain and thereby vasoconstriction of the DA. Since ion channel expression is lower in preterm infants, oxygen induced functional vasoconstriction is attenuated in comparison with full term newborns. Furthermore, the preterm DA is more sensitive to both PGE2 and NO compared to the term DA pushing the balance toward less constriction. In this review we explain the physiology of DA patency in utero and subsequent postnatal functional closure. We will focus on the pathobiology of PDA in preterm infants and the (un)intended effect of antenatal exposure to medication on both fetal and neonatal DA vascular tone.

Role of Phosphodiesterase 5 (PDE5) in Breast Cancer Stroma: Implications for Targeted Therapy

Breast cancers are heterogeneous tissues comprised of multiple components, including tumor and microenvironment cells. Cancer‐associated fibroblasts (CAFs) are an important cell type in tumor‐associated stroma with multiple roles in tumor initiation and promotion. While the significance of CAFs is well recognized, the treatment of CAFs in clinical practice has not yet been established. Our previous studies have shown that the overexpression of phosphodiesterase (PDE) 5, a metallohydrolase which catalyzes the hydrolytic breakdown of cGMP, enhances the invasive potential of breast cancer cells and reduces survival in breast cancer patients. To extend these observations, we propose to assess the function of PDE5 in tumor microenvironment, to further highlight the potential benefit of targeting PDE5.Our results evidenced, for the first time, PDE5 mRNA and protein expression in CAFs isolated from biopsies of primary human breast tumors. PDE5 expression is increased in human breast cancer stroma compared with normal breast stroma and was correlated to a shorter overall survival in patients. Treatment with PDE5 inhibitors (i.e. sildenafil and tadalafil) significantly inhibited CAF proliferation, motility and invasiveness. To better examine the significance of PDE5 expression in stromal fibroblasts, PDE5 was stably integrated into mouse embryonic fibroblasts (MEFs) and cell proliferation, motility and invasion were investigated. PDE5 transformed MEFs towards a cancer‐associated fibroblast phenotype, as evidenced by increased expression of CAF markers along with enhanced proliferative, migratory and invasive capabilities. Coculture experiments showed that proliferation and motility of human breast cancer cells was increased by PDE5‐overexpressing MEFs compared to vector‐expressing MEFs, suggesting that stromal PDE5 contributes to heterotypic communications within breast cancer. An enriched production of the chemokine CXCL16 was revealed in PDE5‐expressing clones, as evidenced by cytokine array and confirmed by realtime PCR, suggesting a role for this molecule in mediating the tumor‐promoting effects of PDE5 expression in breast stroma. In line with these findings, exposure of CAFs to PDE5 inhibitors was associated with a reduced expression of CXCL16. More importantly, expression of CXCL16 in breast cancer stroma showed a strong correlation with PDE5 as well as with a poor patient survival.In conclusion, PDE5 is overexpressed in breast cancer stroma and enhances the tumor‐stimulatory activities of fibroblasts, highlighting this enzyme as a novel prognostic candidate and an attractive target for future therapy in breast cancers, having already addressed the delivery, stability, and toxicity issues of PDE5 inhibitors in other diseases.Support or Funding InformationMy First AIRC Grant (MFAG) #16899 to I. BaroneThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Comparison of the Effects of Tadalafil and α1-Adrenoceptor Antagonists on Spontaneous Seminal Emission and Electrical Field Stimulation-Induced Seminal Vesicle Contraction in Rats

BackgroundAlthough numerous reports have shown that α1-adrenoceptor (α1-AR) antagonists, which are used to treat benign prostatic hyperplasia (BPH), can cause ejaculatory disorders, few studies have investigated whether the phosphodiesterase 5 (PDE5) inhibitor tadalafil has such adverse effects. In this study, we compared the effects of tadalafil and α1-AR antagonists on seminal emission and their mechanisms of action. AimTo evaluate in normal rats the possible effects of tadalafil on spontaneous seminal emission (SSE) and seminal contraction evoked by hypogastric nerve stimulation. MethodsMale Sprague-Dawley rats were used. To assess SSE, plastic corsets were fitted around the thorax and upper abdomen of male Sprague–Dawley rats to prevent genital autogrooming. Rats were treated orally with tadalafil or an α1-AR antagonist (silodosin, naftopidil, or tamsulosin) for 3 days and housed in wire-bottomed cages. Ejaculatory plugs dropped on the bottoms of the cages were counted and weighed. To assess the intraluminal pressure of seminal vesicles, the hypogastric nerve of urethane-anesthetized rats was isolated and electrically stimulated. After stabilization of seminal vesicle contraction, the rats were intravenously administered test drugs. The expression of PDE5, endothelial nitric oxide synthetase (eNOS), and neuronal NOS (nNOS) in the seminal vesicle and vas deferens were measured by reverse-transcription polymerase chain reaction. Main Outcome MeasureThe number and weight of the ejaculatory plugs produced by corset-fitted rats and the intraluminal pressure of the seminal vesicle were evaluated. ResultsTadalafil did not affect the number or weight of the ejaculatory plugs of corset-fitted rats, whereas all α1-AR antagonists decreased both in a dose-dependent manner. The α1-AR antagonists, but not tadalafil, inhibited the seminal vesicle contraction evoked by electrical stimulation of the hypogastric nerve. The seminal vesicle and vas deferens expressed higher levels of PDE5 and eNOS mRNA and lower levels of nNOS mRNA relative to the urethra. Clinical ImplicationsTadalafil can be a treatment option in cases where there is concern about negative effects on seminal emission. Strengths and LimitationsWe demonstrated different effects of tadalafil and 3 α1-AR antagonists on rat SSE and their mechanisms of action by measuring seminal vesicle contractility in vivo. A limitation is that we used normal rats, not BPH model rats, and so our results might not apply to human BPH patients. ConclusionTadalafil did not inhibit spontaneous seminal emission or electrical field stimulation–induced seminal vesicle contraction in normal rats. The NO–cyclic guanosine monophosphate pathway is unlikely to be involved in the inhibition of seminal vesicle contraction in normal rats.Yoshinaga R, Fukui T, Yoshifuji M, et al. Comparison of the Effects of Tadalafil and α1-Adrenoceptor Antagonists on Spontaneous Seminal Emission and Electrical Field Stimulation-Induced Seminal Vesicle Contraction in Rats. J Sex Med 2019;16:680–690.

Supplemental study on 2', 3'-Cyclic Nucleotide 3'-Phosphodiesterase (CNPase) activity in developing rat spinal cord lesions induced by hexachlorophene and cuprizone.

In a previous study, we showed that 2’, 3’-Cyclic Nucleotide 3’-Phosphodiesterase (CNPase) expression is induced in different temporal patterns in the cerebrum, cerebellum and medulla oblongata of hexachlorophene (HCP) and cuprizone (CPZ) treated rats. Here, we additionally examined the histopathological changes and CNPase expression in the spinal cord to clarify the reproducibility of different temporal patterns of CNPase expression in the spinal cord showing low degree or lack of spongy changes. Spongy changes were observed in HCP-treated rats, but not in CPZ-treated rats. Immunohistochemistry showed that intense expression of CNPase was not induced following HCP or CPZ treatment. Our data reveal that expression intensity of CNPase may be dependent on the degree of HCP- and CPZ-induced damage of the myelin sheath.

The cGMP-Degrading Enzyme Phosphodiesterase-5 (PDE5) in Cerebral Small Arteries of Older People.

Cerebral small vessel disease in deep penetrating arteries is a major cause of lacunar infarcts, white matter lesions and vascular cognitive impairment. Local cerebral blood flow in these small vessels is controlled by endothelial-derived nitric oxide, which exerts a primary vasodilator stimulus on vascular myocytes, via cytoplasmic cyclic GMP. Here, we investigated whether the cGMP-degrading enzyme phosphodiesterase-5 (PDE5) is present in small penetrating arteries in the deep subcortical white matter of older people. Frontal cortical tissue blocks were examined from donated brains of older people (n = 42, 24 male: 18 female, median age 81, range: 59-100 years). PDE5, detected by immunohistochemical labeling, was graded as absent, sparse, or abundant in vascular cells within small arteries in subcortical white matter (vessel outer diameter: 20-100 µm). PDE5 labeling within arterial myocytes was detected in all cases. Degree of PDE5 expression (absent, sparse, or abundant) was not associated with age or with neuropathological diagnosis of small vessel disease. In conclusion, PDE5 is present in vascular myocytes within small penetrating arteries in older people. This is a potential molecular target for pharmacological interventions.

Phosphodiesterase expression in the normal and failing heart

The number of patients with heart failure with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF) is increasing, and for HFpEF, no therapies have clinical benefit. It has been hypothesized that PKG attenuates pathological remodelling, and increasing cGMP would be beneficial for patients with HF. However, neither the RELAX nor NEAT-HFpEF trial showed benefit. But there is still enthusiasm for increasing cGMP in patients with HF, which highlight the need to determine the expression of PDEs in cardiac muscle. This study used immunoblotting to examine the expression of the PDEs that have been suggested to be targets for therapy of HF in both canines (normal and HFpEF) and humans (normal and HFrEF). Our results demonstrate PDE1C and PDE3A are expressed in cardiac muscle, but we could not detect the expression of PDE2A, PDE5A, PDE7A and PDE9A in cardiac tissue lysates from either normal or failing hearts. Thus, one should not expect a clinical benefit for a therapy targeting these PDEs in heart failure, which highlights the importance of rigorous demonstration of the target of therapy prior to undertaking a clinical trial.

MiR-19b Functions as a Potential Protector in Experimental Autoimmune Encephalomyelitis.

MicroRNA-19b (miR-19b) is essential in determining oligodendroglia proliferation. Phosphatase and tensin homologue on chromosome 10 (PTEN) is considered the target of miR-19b and participates in oligodendrocyte differentiation and proliferation. Murine EAE was induced by myelin oligodendrocyte glycoprotein (MOG35- 55). For EAE reversal, artificially synthesized agomiR-19b was intravenous injected after immunization. We found that the expression of miR-19b is significantly reduced in an experimental autoimmune encephalomyelitis (EAE) mouse model. This downregulation, which is associated with the neurological scores, can be dramatically ameliorated by agomiR-19b. Our results show that agomiR-19b increases the expression of myelin basic protein (MBP) and cyclic nucleotide phosphodiesterase (CNP), which are regularly utilized as molecular markers of oligodendrocytes. Furthermore, our study also revealed that miR-19b probably affects the expression of PTEN in the EAE model. These results indicate that the restoration of miR-19b probably exerts its therapeutic effect by affecting PTEN in the pathogenesis of EAE.

Analysis of the nitric oxide-cyclic guanosine monophosphate pathway in experimental liver cirrhosis suggests phosphodiesterase-5 as potential target to treat portal hypertension.

AIMTo investigate the potential effect of inhibitors of phosphodiesterase-5 (PDE-5) for therapy of portal hypertension in liver cirrhosis.METHODSIn the rat model of thioacetamide-induced liver fibrosis/cirrhosis the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway was investigated. Expression and localization of PDE-5, the enzyme that converts vasodilating cGMP into inactive 5’-GMP, was in the focus of the study. Hepatic gene expression of key components of the NO-cGMP pathway was determined by qRT-PCR: Endothelial NO synthase (eNOS), inducible NO synthase (iNOS), soluble guanylate cyclase subunits α1 and β1 (sGCa1, sGCb1), and PDE-5. Hepatic PDE-5 protein expression and localization were detected by immunohistochemistry. Serum cGMP concentrations were measured using ELISA. Acute effects of the PDE-5 inhibitor Sildenafil (0.1 mg/kg or 1.0 mg/kg) on portal and systemic hemodynamics were investigated using pressure transducers.RESULTSHepatic gene expression of eNOS (2.2-fold; P = 0.003), sGCa1 (1.7-fold; P = 0.003), sGCb1 (3.0-fold; P = 0.003), and PDE-5 (11-fold; P = 0.003) was increased in cirrhotic livers compared to healthy livers. Overexpression of PDE-5 (7.7-fold; P = 0.006) was less pronounced in fibrotic livers. iNOS expression was only detected in fibrotic and cirrhotic livers. In healthy liver, PDE-5 protein was localized primarily in zone 3 hepatocytes and to a lesser extent in perisinusoidal cells. This zonation was disturbed in cirrhosis: PDE-5 protein expression in perisinusoidal cells was induced approximately 8-fold. In addition, PDE-5-expressing cells were also found in fibrous septa. Serum cGMP concentrations were reduced in rats with cirrhotic livers by approximately 40%. Inhibition of PDE-5 by Sildenafil caused a significant increase in serum cGMP concentrations [+ 64% in healthy rats (P = 0.024), + 85% in cirrhotic rats (P = 0.018)]. Concomitantly, the portal venous pressure was reduced by 19% in rats with liver cirrhosis.CONCLUSIONOverexpression and abrogated zonation of PDE-5 likely contribute to the pathogenesis of cirrhotic portal hypertension. PDE-5 inhibition may therefore be a reasonable therapeutic approach for portal hypertension.

Novel effect of sildenafil on hair growth

BackgroundSildenafil, a phosphodiesterase 5 (PDE5) inhibitor, is known to increase the intracellular level of cyclic guanosine monophosphate (cGMP), which causes vasodilation. However, the effect of sildenafil on human hair follicles (hHFs) is unknown. ObjectiveThe purpose of this study was to determine the role of sildenafil in hair growth. MethodsWe investigated the expression of PDE5 in human dermal papilla cells (hDPCs) and hHFs. The effects of sildenafil on hDPC proliferation were evaluated using BrdU assays. The mRNA expression of growth factors and extracellular signal-regulated kinase (ERK) phosphorylation were investigated using real-time PCR and western blotting, respectively. Additionally, anagen induction and perifollicular vessel formation were evaluated using an in vivo mice model. ResultsWe confirmed high expression of PDE5 in hDPCs and hHFs. Sildenafil enhances proliferation of hDPCs and up-regulates the mRNA expression of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF), which are responsible for hair growth. Additionally, sildenafil up-regulates the levels of phosphorylated ERK and accelerates anagen induction by stimulating perifollicular vessel formation after topical application in mice. ConclusionOur study demonstrates for the first time, the significant therapeutic potential of sildenafil on hair growth and its potential use in treatment of alopecia.

Abstract 017: Effect of Sildenafil on Nitric Oxide-Mediated Vasodilation in the Human Placenta: an Ex-Vivo Placental Perfusion Study

Preeclampsia (PE) is a serious pregnancy complication characterized by suboptimal placentation, leading to increased vascular resistance and generalized endothelial dysfunction. A promising treatment is sildenafil, a phosphodiesterase-5 (PDE5) inhibitor that enhances nitric oxide (NO) mediated vasodilation. Although there are currently sildenafil trials ongoing in pregnant women, the effects of sildenafil on the placenta are still unknown. Placentas of healthy (n=17), early-onset (Eo)PE (n=6) and late-onset (Lo)PE (n=5) pregnancies were dually perfused, pre-constricted with serotonin, and subsequently exposed to the NO donor SNP in the absence or presence of 1 μmol/L sildenafil. Two healthy placentas were perfused with sildenafil on the maternal side to study placental transfer. Placental protein expression of PDE5, PDE1A, eNOS and iNOS was assessed using Western blot. Mean baseline pressure ±SEM was significantly lower (p&lt;0.05) in EoPE (22.3±2.8 mmHg) and LoPE (22.8±1.7 mmHg) vs. healthy placentas (33.1±2.2 mmHg). There was no effect of sildenafil on baseline pressure or serotonin-induced pre-constriction. Sildenafil tended to enhance vasodilatory response to 10 -6 M SNP in healthy (mean pressure decrease 4.3±0.8 vs. 8.1±1.9 mmHg, p=0.1) and LoPE placentas (3.0±1.0 vs. 7.3±3.2 mmHg), while no improvement was seen in EoPE placentas (6.0±2.0 vs. 5.0±1.0 mmHg). When sildenafil was added at the maternal side, average fetal-maternal concentration ratio was 0.22 after 3 hours of perfusion, as compared to 0.86 for antipyrine, a freely diffusing molecule. Placental levels of PDE1A tended to be higher in PE (p=0.08), while no differences in expression of PDE5, eNOS and iNOS were observed between PE and healthy placentas. Our study reveals that PE placentas have a significantly lower baseline pressure compared to healthy placentas, possibly due to lower resistance in the feto-placental vasculature as a compensation mechanism for the increased resistance in the spiral arteries. Although sildenafil tended to enhance vasodilation in healthy and LoPE placentas, it did not have those beneficial effects in EoPE. Possibly PDE1A-selective inhibitors should be applied in PE, or PDE is not the appropriate target for restoring disturbed vasodilation.

Mechanisms Underlying the Clinical Effects of Apremilast for Psoriasis.

Psoriasis is a chronic, systemic, inflammatory disease with manifestations resulting from a dysregulated immune response. In psoriatic skin, expression of all phosphodiesterase 4 (PDE4) isoforms (A-D), part of a family of enzymes known to regulate cyclic adenosine monophosphate levels and immune homeostasis, is elevated compared with healthy controls. Agents that inhibit the enzymatic activity of PDE4, the predominant PDE in most immune cells, exert well-recognized anti-inflammatory effects. Apremilast is a selective PDE4 inhibitor approved for the treatment of adults with moderate to severe plaque psoriasis and/or psoriatic arthritis. In vitro and in vivo investigations have demonstrated the beneficial impact of apremilast treatment on PDE4 activity, inflammatory signal expression, and dermal psoriasiform signs. In patients with moderate to severe psoriasis, treatment with apremilast is associated with significant reductions in plasma levels of interleukin (IL)-17F, IL-17A, IL-22, and tumor necrosis factor-α compared with placebo as early as week 4; decreases in cytokine levels were sustained with continued treatment. Multivariate analyses demonstrated that while changes in IL-17F are the most important predictor of improvement in Psoriasis Area and Severity Index scores, apremilast exerts synergistic attenuating effects among a key group of cytokines involved in the pathology of psoriasis, and these effects correlate with improved skin symptoms. These in vitro and clinical data demonstrate that the beneficial effects of apremilast on known inflammatory mediators are associated with its clinical efficacy. J Drugs Dermatol. 2018;17(8):835-840. <p>THIS ARTICLE HAD BEEN MADE AVAILABLE FREE OF CHARGE. PLEASE SCROLL DOWN TO ACCESS THE FULL TEXT OF THIS ARTICLE WITHOUT LOGGING IN. NO PURCHASE NECESSARY. PLEASE CONTACT THE PUBLISHER WITH ANY QUESTIONS.</p>.