Role of Nrf2/HO-1 and PI3K/Akt Genes in the Hepatoprotective Effect of Cilostazol

Cilostazol attenuates cisplatin-induced acute liver injury by targeting the SIRT1/AMPK/PGC-1α signaling pathway, with an impact on miRNA-34a

The dominant chemotherapeutic agent, cisplatin (CP), is widely used to manage various cancer types. Despite its effectiveness, CP use is associated with severe hepatotoxicity. Cilostazol (CSZ), a selective phosphodiesterase III inhibitor, has recently demonstrated remarkable anti-inflammatory and anti-apoptotic properties in different diseases. Additionally, it exhibits hepatoprotective effects against various forms of liver injury. Hence, this study aimed to assess the potential hepatoprotective and ameliorative effects of CSZ on CP-induced acute liver injury (ALI) and to elucidate the underlying molecular mechanisms. To achieve this, ALI was induced by a single injection of CP (20 mg/kg; i.p.) in male Wistar rats pretreated with CSZ (5 or 10 mg/kg) administered orally for one week. The findings revealed that CSZ effectively reversed CP-induced hepatic dysfunction, as evidenced by notable liver function tests and improvements in histological examination. Additionally, CSZ protected against CP-mediated liver oxidative stress by decreasing MDA levels while increasing GSH and GPx levels and enhancing SOD activity. Furthermore, CSZ exhibited a potent anti-inflammatory effect, reducing the expression of pro-inflammatory cytokines, including NF-κB, IL-1β, and TNF-α. Regarding hepatocyte apoptosis, CSZ suppressed Bax immunoexpression and caspase-3 and caspase-9 levels while enhancing Bcl-2 expression, thereby mitigating hepatic cell death. The hepatoprotective effects of CSZ could be attributed to the regulation of the miRNA-34a/AMPK/SIRT1/PGC-1α signaling pathway, leading to the activation of the Nrf2/HO-1-mediated antioxidative defense mechanism. In conclusion, CSZ could be a promising therapeutic agent for preventing CP-induced ALI, potentially improving the quality of life for cancer patients.

Dapagliflozin alleviates thioacetamide induced-liver fibrosis in rats via controlling the Nrf2/HO-1 and TLR4/TGF-β1/PI3K signaling pathways

OBJECTIVES

Because liver fibrosis causes several insults that can result in death, it is regarded as an epidemic health issue. As "an inhibitor of the sodium-glucose cotransporter-2 (SGLT2)," Dapagliflozin (Dapa) is one of the newest anti-diabetic drugs used to treat type 2 diabetes mellitus. Dapa's antioxidant, anti-inflammatory, and antifibrotic properties produced positive impacts in numerous human and animal models. Due to Dapa's previously documented properties, we planned this investigation to elucidate the protective function of Dapa in male rat liver fibrosis caused by thioacetamide (TAA) as well as the expected pathways.

METHODS

There were four groups of 24 rats: a control group, a TAA group that received (100 mg/kg b.wt intraperitoneally twice a week for 6 weeks), "TAA + Dapa" groups that given oral Dapa at (1 and 2 mg/kg b.wt. for 4 weeks in addition to TAA injections).

RESULTS

It was shown that TAA injections increased toll-like receptor 4 (TLR4) (509.6%), tumor necrosis factor (TNF-α) (298.8%), alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), interleukin-6 (IL-6) (330.9%), phosphotidylinositol-3-kinase (PI3K) (428.9% %), and transforming growth factor-beta (TGF-β1) (416.6%) levels. All of these markers were considerably reduced by Dapa treatment. In addition, reduced glutathione (GSH), nuclear factor erythroid 2-related factor 2 (Nrf2) (79%), albumin, Heme-oxygenase 1 (HO-1) (69%), and superoxide dismutase (SOD) were all decreased after TAA injection; however, they were restored by Dapa administration. The Dapa-treated groups had higher Nrf2 and HO-1 gene expressions, based on the results of PCR. Biochemical outcomes were validated by histopathological results. Immunohistopathological study revealed that DAPA treatment decreased caspase-3 and alpha-smooth Muscle Actin (αSMA) expression.

CONCLUSION

Due to its interactions with the Nrf2/HO-1 and TLR4 pathways, our research showed that Dapa had antioxidant and anti-inflammatory qualities against TAA-induced liver fibrosis.

miR-328-3p suppresses hepatocellular carcinoma progression by regulating HMOX1 expression

INTRODUCTION

Most oncogenic genes contribute to cancer progression, but their role and regulatory mechanisms are not yet fully understood in hepatocellular carcinoma (HCC). This study aimed to explore the role of miR-328-3p and the regulatory relationship between miR-328-3p and HMOX1 in HCC.

METHODS

We utilized Cox and LASSO regression to identify a panel of oncogenic genes associated with hepatocellular carcinoma (HCC) progression within the TCGA-LIHC cohort and the GSE104580 dataset. The expression levels of the hub gene, HMOX1, were assessed in HCC cell lines using qPCR. The functional roles of miR-328-3p and HMOX1 were evaluated through a series of in vitro assays, including CCK-8 for proliferation, colony formation, wound healing, and Transwell assays for migration and invasion. The direct interaction between miR-328-3p and HMOX1 was explored using a luciferase reporter assay, Western blot (WB) for protein expression analysis, and functional assays to determine the impact on cell proliferation and migration.

RESULTS

Eight candidate genes (BIRC5, TNSF4, SPP1, HMOX1, ADM, RBP2, IGF1, and LECT2) were screen out. The hub gene HMOX1 among had high expression level in HCC cell lines. High HMOX1 expressing cell line had significantly increased proliferation and migration capacities. Moreover, HMOX1 was identified as a target of miR-328-3p, which regulated the HMOX1 expression in qPCR and WB assays. High miR-328-3p expressing HCC cell had diminished capacities for proliferation and migration. However, concurrent upregulation of HMOX1 expression resulted in enhanced proliferative and migratory abilities in these cells.

CONCLUSION

Our study has advanced our understanding of the roles of miR-328-3p and HMOX1 in HCC, demonstrating the inhibitory effect of miR-328-3p on the oncogenic activity of HMOX1. Hence, these results revealed the function of miR-328-3p and a novel mechanistic pathway for HCC and suggested the potential therapeutic targeting of miR-328-3p and HMOX1 for HCC intervention strategies.

Effect of Hibiscus sabdariffa L. leaf flavonoid-rich extract on Nrf-2 and HO-1 pathways in liver damage of streptozotocin-induced diabetic rats

This study investigated the effects of flavonoid-rich extract from Hibiscus sabdariffa L. (Malvaceae) leaves on liver damage in streptozotocin-induced diabetic rats by evaluating various biochemical parameters, including the molecular gene expressions of Nrf-2 and HO-1 as well as histological parameters. The extract was found to significantly reduce liver damage, as evidenced by lower levels of fragmented DNA and protein carbonyl concentrations. Oxidative stress markers, including malondialdehyde (MDA) level, were also significantly (p < 0.05) decreased, while antioxidant biomarkers, like reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) were enhanced. Additionally, the extract improved the activities of key liver enzymes, including phosphatases and transaminases, and increased albumin levels. Importantly, the study demonstrated that H. sabdariffa extract effectively regulated the expression of Nrf-2 and HO-1, suggesting a significant role in mitigating liver damage. These findings highlight its potential as a therapeutic agent for liver protection in diabetic conditions.

Erythropoietin Suppresses the Hepatic Fibrosis Caused by Thioacetamide: Role of the PI3K/Akt and TLR4 Signaling Pathways

Erythropoietin (EPO) is recognized for its function in erythropoiesis; however, its potential antifibrotic effect against liver fibrosis remains unknown. This study examined whether EPO affects thioacetamide (TAA)-induced liver fibrosis by concentrating on the Toll-like receptor 4 (TLR4) cascade and the phosphatidylinositol 3-kinase (PI3K)/Akt pathway as possible pathways. Male Wistar rats were randomized into four groups, which included: the negative control group, the TAA group (intraperitoneal; TAA 100 mg/kg three times per week for 2 weeks), and EPO-treated groups (150 and 300 IU/kg, i.p.) for 2 weeks after TAA injections. EPO attenuated hepatic fibrosis in a dosage-dependent way, as manifested by the diminution in serum alanine aminotransferase and aspartate aminotransferase activities, as well as the increase in albumin level. EPO inhibited the increase in tissue levels of tumor necrosis factors-α, interleukin-1β, transforming growth factor-β1, and TLR4 and raised tissue levels of PI3K and p-PI3K. EPO antioxidant properties were demonstrated by restoring hepatic glutathione and superoxide dismutase by preventing the accumulation of hepatic malondialdehyde. Further, EPO increased the protein expression of PI3K and Akt and decreased TLR4 protein expression. Immunohistochemically, EPO treatment altered tissue histology and downregulated mitogen-activated protein kinase protein expression. Overall, the research suggested that EPO could prevent TAA-induced hepatic fibrosis through upregulating the PI3K/Akt signaling cascade and downregulation the TLR4 downstream axis.

Cilostazol novel neuroprotective mechanism against rotenone-induced Parkinson's disease in rats: Correlation between Nrf2 and HMGB1/TLR4/PI3K/Akt/mTOR signaling

Neuroinflammation induced by activation of the high mobility group box 1/ toll-like receptor 4 (HMGB1/TLR4) axis is one of the principal mechanisms involved in dopaminergic neuronal loss in Parkinson's disease (PD), and its activation exacerbates oxidative stress augmenting neurodegeneration.

AIMS

This study investigated the novel neuroprotective effect of cilostazol on rotenone-intoxicated rats focusing on the HMGB1/TLR4 axis, erythroid-related factor 2 (Nrf2)/hemeoxygenase-1 (HO-1), and phosphoinositide 3-kinase (PI3K)/Protein kinase B (Akt)/the mammalian target of rapamycin (mTOR) pathway. The aim is extended to correlate the Nrf2 expression with all assessed parameters as promising therapeutic targets for neuroprotection.

MAIN METHODS

Our experiment was designed as follows: vehicle group, cilostazol group, rotenone group (1.5 mg/kg, s.c), and the rotenone pretreated with cilostazol (50 mg/kg, p.o.) group. Eleven rotenone injections were injected day after day, while cilostazol was administered daily for 21 days.

KEY FINDINGS

Cilostazol significantly improved the neurobehavioral analysis, the histopathological examination, and dopamine levels. Moreover, the immunoreactivity of tyrosine hydroxylase (TH) in substantia nigra pars compacta (SNpc) enhanced. These effects were associated with enhancement of the antioxidant expression of Nrf2 and HO-1 by 1.01 and 1.08-fold, respectively, and repression of HMGB1/TLR4 pathway by 50.2 % and 39.3 %, respectively. Upregulation of the neuro-survival PI3K and Akt expression by 2.26 and 2.69-fold, respectively, and readjusting mTOR overexpression.

SIGNIFICANCE

Cilostazol exerts a novel neuroprotective strategy against rotenone-induced neurodegeneration via activation of Nrf2/HO-1, suppression of HMGB1/TLR4 axis, upregulation of PI3K/Akt besides mTOR inhibition that compels more investigations with different PD models to clarify its precise role.

Combined carvacrol and cilostazol ameliorate ethanol-induced liver fibrosis in rats: Possible role of SIRT1/Nrf2/HO-1 pathway

Carvacrol is a natural phenolic monoterpenoid, and cilostazol is a selective phosphodiesterase-3 inhibitor with antioxidant, anti-inflammatory and antiapoptotic effects. This experiment aimed to explore the hepatoprotective effects of carvacrol and cilostazol alone and in combination against alcoholic liver fibrosis (ALF), and the underlying mechanisms, using silymarin as a reference anti-fibrotic product. ALF was induced by oral administration of ethanol (1 ml/100 g/day) thrice per week. Silymarin (100 mg/kg), carvacrol (70 mg/kg), cilostazol (50 mg/kg), or carvacrol + cilostazol combination were administered daily and concurrently with ethanol for six weeks. Hepatic changes were evaluated by quantifying serum biomarkers of liver injury, hepatic MDA, GSH and NOx as oxidative stress markers, interleukin (IL)-10 as an anti-inflammatory cytokine, 4-hydroxyproline (4-HYP) as a collagen synthesis indicator, transforming growth factor (TGF)-β1 as a profibrogenic cytokine, α-smooth muscle actin (α-SMA) as a marker of hepatic stellate cells (HSCs) activation, histopathological (necroinflammation and fibrosis) scores and hepatic sirtuin-1 (SIRT1), nuclear factor-erythroid 2-related factor 2 (Nrf2), and hemeoxygenase-1 (HO-1) mRNA levels. Our results showed that carvacrol, cilostazol, and their combination significantly ameliorated ethanol-induced hepatic fibrosis manifested as improving hepatic functions and histopathological features, attenuating α-SMA immunostaining, reducing TGF-β1 and 4-HYP levels, suppressing oxidativeinjury and elevating IL-10 contents. Such effects were accompanied by upregulating SIRT1, Nrf2 and HO-1 genes. This work disclosed for the first time the hepatoprotective effect of carvacrol against ALF and, to a greater extent, with carvacrol + cilostazol combination that could be partially accredited to SIRT1/Nrf2/HO-1 pathway with consequent antioxidant, anti-inflammatory, and anti-fibrotic features.

Protective effect of cilostazol and verapamil against thioacetamide-induced hepatotoxicity in rats may involve Nrf2/GSK-3β/NF-κB signaling pathway

BACKGROUND

Verapamil (VER) and cilostazol (Cilo) are mostly used as cardiovascular drugs; they have beneficial effects on different organs toxicities.

AIM

we investigated whether the Nuclear factor erythroid 2-related factor 2 (Nrf2), Glycogen synthase kinase-3β (GSK-3β), and Nuclear factor-kappa B (NF-κB) pathway involved in the protective role of these drugs against Thioacetamide (TAA) induced hepatotoxicity.

METHOD

male rats were randomized divided into five groups, each group (n = 10): control, TAA, VER+TAA, Cilo+TAA, and VER+Cilo+TAA groups. Hepatotoxicity induced in rats by TAA injection once on the 7th day of the experiment.

RESULTS

TAA-induced hepatotoxicity indicated by a significant elevated in serum markers (Alanine aminotransferases (ALT), Aspartate aminotransferases (AST), and bilirubin), oxidative stress markers (Malondialdehyde (MDA), and Nitric oxide (NO)), and protein levels markers (NF-κB, and S100 calcium-binding protein A4 (S100A4)). Also, TAA decreased Nrf2, and increased GSK-3β genes expression. Histopathological alterations in the liver also appeared as a response to TAA injection. On the other hand VER and/or Cilo significantly prevented TAA-induced hepatotoxicity in rats through significantly decreased in ALT, AST, bilirubin, MDA, NO, NF-κB, and S100A4 protein levels. Also, they increased Nrf2 and decreased GSK-3β genes expression which caused improvement in the histopathological changes of the liver.

CONCLUSION

the addition of verapamil to cilostazol potentiated the hepatoprotective activity, and inhibited the progression of hepatotoxicity caused by TAA through the Nrf2/GSK-3β/NF-κBpathway and their activity on oxidative stress, inflammation, and NF-κB protein expression.

Cilostazol attenuates cardiac oxidative stress and inflammation in hypercholesterolemic rats

Atherosclerosis is a multifactorial chronic disease associated with pro-inflammatory and pro-oxidative cardiovascular states. Cilostazol, a selective phosphodiesterase 3 inhibitor (PDE3), is clinically used in the treatment of intermittent claudication and secondary prevention of cerebral infarction. The aim of this study was to evaluate the cardioprotective effects of cilostazol and the molecular mechanisms involved in hypercholesterolemic rats. Male Wistar rats were divided into four groups: control group (C) and control + cilostazol group (C+CILO), that were fed a standard chow diet, and hypercholesterolemic diet group (HCD) and HCD + cilostazol (HCD+CILO) that were fed a hypercholesterolemic diet. Cilostazol treatment started after 30 days for C+CILO and HCD+CILO groups. Animals were administered cilostazol once a day for 15 days. Subsequently, serum and left ventricles were extracted for evaluation of lipid profile, inflammatory, and oxidative biomarkers. The HCD group displayed increased serum lipid levels, inflammatory cytokines production, and cardiac NF-kB protein expression and decreased cardiac Nrf2-mediated antioxidant activity. Conversely, the cilostazol treatment improved all these cardiac deleterious effects, inhibiting NF-kB activation and subsequently decreasing inflammatory mediators, reestablishing the antioxidant properties through Nrf2-mediated pathway, including increased SOD, GPx, and catalase expression. Taken together, our results indicated that cilostazol protects hypercholesterolemia-induced cardiac damage by molecular mechanisms targeting the crosstalk between Nrf2 induction and NF-kB inhibition in the heart.

Protective effect of rutin and β-cyclodextrin against hepatotoxicity and nephrotoxicity induced by lambda-cyhalothrin in Wistar rats: biochemical, pathological indices and molecular analysis

BACKGROUND

This study aimed to assess hepatotoxicity and nephrotoxicity of Lambda-cyhalothrin (LCT) and the protective effect of rutin alone and in combination with β-cyclodextrin (β-CD).

MATERIALS AND METHODS

Male Wistar rats were divided into five groups: Group 1: was used as a control and received a standard diet and water. Group 2, 3, 4 and 5 were orally administered with LCT (7.6 mg/kg body weight), rutin (200 mg/kg body weight) LCT and rutin (at the same doses as in Group 2 and Group 3), and LCT and a mixture of rutin with β-CD (400 mg/kg body weight), respectively. All experimental animals were orally gavaged 5 days/week for 60 days.

RESULTS

Our data revealed that LCT-induced liver and kidney injuries were related to the up-regulated expression of TNF-α and down-regulated expression of NRF-2 genes mRNA, whereas these effects were reversed with rutin treatment. LCT-induced oxidative stress altered the histological picture, and the hematological and biochemical parameters.

CONCLUSION

Treatment with a rutin-β-CD complex had preventive potential against LCT via suppression of oxidative stress and augmentation of the antioxidant defense system.

Oxyberberine, a novel HO-1 agonist, effectively ameliorates oxidative stress and inflammatory response in LPS/D-GalN induced acute liver injury mice via coactivating erythrocyte metabolism and Nrf2 signaling pathway

Oxyberberine (OBB), a main gut-mediated metabolite of Phellodendron chinense Cortex (PC), exhibits prominent protective property against acute liver injury (ALI). Heme oxygenase-1 (HO-1) is a vital molecule in attenuating acute and chronic liver injury for its prominent anti-oxidative injury and anti-inflammation properties. The present study was performed to investigate the hepatoprotective role of OBB through HO-1 signaling pathway in lipopolysaccharide/D-galactosamine (LPS/D-GalN) induced ALI. Our results indicated that PC treatment improved survival rate and its metabolite OBB evidently improved histopathological deteriorations and liver function. Additionally, OBB dramatically ameliorated hepatic oxidative stress and inflammation. Besides, OBB exerted remarkable HO-1 agonistic activity, even be comparable to hemin (a HO-1 inducer), as evidenced by increased HO-1 level, carbon monoxide and bilirubin activities, which are the markers of erythrocyte metabolism. Moreover, OBB modulated the parameters of inflammation and oxidative stress through HO-1 dependent pathway. Beyond this, OBB also notably suppressed the translocation of p65, enhanced antioxidation defense genes expressions, promoted the degradation of Kelch-like ECH-associated protein 1 (Keap1) and the nuclear translocation of nuclear factor-erythroid-2-related factor 2 (Nrf2). In conclusion, OBB could be the principle active metabolite substance of PC and exert excellent hepatoprotective effects via inducing HO-1 through coactivation of erythrocyte metabolism and Nrf2/HO-1 pathway.

Model difference in the effect of cilostazol on the development of experimental pulmonary hypertension in rats

BACKGROUND

Preventing pulmonary vascular remodeling is a key strategy for pulmonary hypertension (PH). Causes of PH include pulmonary vasoconstriction and inflammation. This study aimed to determine whether cilostazol (CLZ), a phosphodiesterase-3 inhibitor, prevents monocrotaline (MCT)- and chronic hypoxia (CH)-induced PH development in rats.

METHODS

Fifty-one male Sprague-Dawley rats were fed rat chow with (0.3% CLZ) or without CLZ for 21 days after a single injection of MCT (60 mg/kg) or saline. Forty-eight rats were fed rat chow with and without CLZ for 14 days under ambient or hypobaric (air at 380 mmHg) CH exposure. The mean pulmonary artery pressure (mPAP), the right ventricle weight-to-left ventricle + septum weight ratio (RV/LV + S), percentages of muscularized peripheral pulmonary arteries (%Muscularization) and medial wall thickness of small muscular arteries (%MWT) were assessed. Levels of the endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (peNOS), AKT, pAKT and IκB proteins in lung tissue were measured using Western blotting. Monocyte chemotactic protein (MCP)-1 mRNA in lung tissue was also assessed.

RESULTS

mPAP [35.1 ± 1.7 mmHg (MCT) (n = 9) vs. 16.6 ± 0.7 (control) (n = 9) (P < 0.05); 29.1 ± 1.5 mmHg (CH) (n = 10) vs. 17.5 ± 0.5 (control) (n = 10) (P < 0.05)], RV/LV + S [0.40 ± 0.01 (MCT) (n = 18) vs. 0.24 ± 0.01 (control) (n = 10) (P < 0.05); 0.41 ± 0.03 (CH) (n = 13) vs. 0.27 ± 0.06 (control) (n = 10) (P < 0.05)], and %Muscularization and %MWT were increased by MCT injection and CH exposure. CLZ significantly attenuated these changes in the MCT model [mPAP 25.1 ± 1.1 mmHg (n = 11) (P < 0.05), RV/LV + S 0.30 ± 0.01 (n = 14) (P < 0.05)]. In contrast, these CLZ effects were not observed in the CH model. Lung eNOS protein expression was unchanged in the MCT model and increased in the CH model. Lung protein expression of AKT, phosphorylated AKT, and IκB was downregulated by MCT, which was attenuated by CLZ; the CH model did not change these proteins. Lung MCP-1 mRNA levels were increased in MCT rats but not CH rats.

CONCLUSIONS

We found model differences in the effect of CLZ on PH development. CLZ might exert a preventive effect on PH development in an inflammatory PH model but not in a vascular structural change model of PH preceded by vasoconstriction. Thus, the preventive effect of CLZ on PH development might depend on the PH etiology.

Cubosomes as a Potential Oral Drug Delivery System for Enhancing the Hepatoprotective Effect of Coenzyme Q10

Coenzyme Q10 (CoQ10) acts as an antioxidant that protects the cells by preventing lipid peroxidation. Owing to its low solubility, CoQ10 has shown poor delivery properties and poor bioavailability. The aim of this study is to develop CoQ10 loaded cubosomes in order to enhance its oral delivery and hepatoprotective activity. Cubosomes are cubic nanostructured systems resulting from the colloidal dispersion of cubic liquid crystalline structure in water. CoQ10 loaded cubosomes were prepared using poloxamer 407 and glyceryl monooleate at three weight ratios (1:2.5, 1:5 and 1:7.5) and were further characterized. They were investigated for their hepatoprotective effect in thioacetamide (TAA) induced hepatotoxicity in Wistar rats. The developed CoQ10 cubosomes exhibited moderate to high entrapment efficiency percentages (44.69-75.96%), nanometric dimensions (132.4-223.2 nm), and negatively charged zeta potential values (<-21.3). In-vitro release profiles showed a sustained release of CoQ10 from the developed cubosomes up to 48 h. In-vivo study revealed an improved hepatoprotective effect of CoQ10 cubosomes via reducing liver enzymes, nitric oxide and malondialdehyde as well as elevating phosphoinositide 3-kinase, catalase and glutathione peroxidase, compared to plain drug. These results were in good agreement with histopathological investigations. Consequently, the developed cubosomes showed a potential effect in enhancing the hepatoprotective activity of CoQ10.

Phosphodiesterase Inhibitors for Alzheimer's Disease: A Systematic Review of Clinical Trials and Epidemiology with a Mechanistic Rationale

BACKGROUND

Preclinical studies, clinical trials, and reviews suggest increasing 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic guanosine monophosphate (cGMP) with phosphodiesterase inhibitors is disease-modifying in Alzheimer's disease (AD). cAMP/protein kinase A (PKA) and cGMP/protein kinase G (PKG) signaling are disrupted in AD. cAMP/PKA and cGMP/PKG activate cAMP response element binding protein (CREB). CREB binds mitochondrial and nuclear DNA, inducing synaptogenesis, memory, and neuronal survival gene (e.g., brain-derived neurotrophic factor) and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α). cAMP/PKA and cGMP/PKG activate Sirtuin-1, which activates PGC1α. PGC1α induces mitochondrial biogenesis and antioxidant genes (e.g.,Nrf2) and represses BACE1. cAMP and cGMP inhibit BACE1-inducing NFκB and tau-phosphorylating GSK3β.

OBJECTIVE AND METHODS

We review efficacy-testing clinical trials, epidemiology, and meta-analyses to critically investigate whether phosphodiesteraseinhibitors prevent or treat AD.

RESULTS

Caffeine and cilostazol may lower AD risk. Denbufylline and sildenafil clinical trials are promising but preliminary and inconclusive. PF-04447943 and BI 409,306 are ineffective. Vinpocetine, cilostazol, and nicergoline trials are mixed. Deprenyl/selegiline trials show only short-term benefits. Broad-spectrum phosphodiesterase inhibitor propentofylline has been shown in five phase III trials to improve cognition, dementia severity, activities of daily living, and global assessment in mild-to-moderate AD patients on multiple scales, including the ADAS-Cogand the CIBIC-Plus in an 18-month phase III clinical trial. However, two books claimed based on a MedScape article an 18-month phase III trial failed, so propentofylline was discontinued. Now, propentofylline is used to treat canine cognitive dysfunction, which, like AD, involves age-associated wild-type Aβ deposition.

CONCLUSION

Phosphodiesterase inhibitors may prevent and treat AD.

Cilostazol protects against cyclophosphamide-induced ovarian toxicity in female rats: role of cAMP and HO-1

Purpose: Cancer rates have been increased among women of reproductive age nowadays. Hence, many young female will be exposed to chemotherapeutic agents as cyclophosphamide (CP), carrying the hazards on female fertility. Cilostazol is a selective phosphodiesterase-3 inhibitor drug which exhibits antioxidant, anti-inflammatory, and anti-apoptotic activities. We aimed in this study to explore the possible protective effects of cilostazol against CP-induced ovarian damage in female rats.Methods: Cilostazol (10 mg/kg/day) was administered orally for 10 days in presence and absence of CP (150 mg/kg IP single dose) treatment. Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen (E2), and anti-Müllerian hormone (AMH) levels were determined. Ovarian oxidative stress parameters along with inflammatory biomarkers were measured. 3,5-Cyclic adenosine monophosphate (cAMP) ovarian level was detected. Ovarian histopathological examination and caspase-3 immunohistochemical study were evaluated.Results: CP-treated rats showed a significant increase in serum levels of FSH and LH with decreased serum E2 and AMH levels with an increase in the ovarian inflammatory and oxidative stress biomarkers besides a significant decrease in cAMP ovarian level with an evident histopathological picture of ovarian damage and a high caspase-3 immunoexpression. Cilostazol pretreatment significantly restored the distributed hormonal levels, the oxidative stress and inflammatory biomarkers to their normal levels with marked improvement in histopathological picture of ovarian damage with a significant decrease in caspase-3 immunoexpression.Conclusions: These data suggest that cilostazol protects against CP- induced ovarian damage, which may be related to an increase in cAMP with subsequent anti-inflammatory, antioxidant, and anti-apoptotic properties.