Dipyridamole decreases inflammatory metalloproteinase-9 expression and release by human monocytes

Dipyridamole Attenuates Experimental Periodontitis by Regulating M1 Macrophage Polarization via PKA/PKG Pathways

AIM

Periodontitis is a chronic inflammatory disease initiated by dysbiosis of the local microbial community. As a non-specific phosphodiesterase inhibitor, dipyridamole features anti-oxidant and anti-inflammatory properties. This study aimed to investigate the effects of dipyridamole in an experimental rat model of periodontitis.

METHODS

Thirty rats were divided randomly into three groups (n = 10): non-ligature group (NL), ligature-induced periodontitis group (L), and ligature-induced periodontitis with dipyridamole administered group (L + D). All rats were euthanized on Day 14. Alveolar bone resorption was analyzed by microcomputed tomography. The mRNA levels of Il1b, Il6, tumor necrosis factor alpha (Tnfa), and inducible nitric oxide synthase (iNos) in gingival tissue were assessed by real-time quantitative polymerase chain reaction (qRT-PCR). Inflammation level, osteoclasts, and macrophages infiltration were analyzed histologically. RAW264.7 macrophages were stimulated with Porphyromonas gingivalis lipopolysaccharide (P.g. LPS) to induce M1 polarization. Different concentration of dipyridamole (0/2/10 μM) was added simultaneously. To explore the role of PKA/PKG pathways, RAW 264.7 macrophages were pretreated with 10 μM H-89 (PKA inhibitor) or 1 μM KT-5823 (PKG inhibitor), respectively. Expression of pro-inflammatory cytokines and M1 markers were detected by qRT-PCR, ELISA, and flow cytometry.

RESULTS

Dipyridamole administration reduced alveolar bone loss, protein levels of inflammatory cytokines, and osteoclastogenesis in rats with experimental periodontitis. It also showed a tendency to decrease mRNA levels of Il1b, Il6, and Tnfa but without significant differences in gingival tissues. Moreover, the infiltration of macrophage and M1 macrophage polarization in gingival tissue of periodontitis rats were inhibited by dipyridamole administration. In addition, dipyridamole could downregulate the gene expression of Il1b and Tnfa, as well as the protein level of TNF-α, CD86, and iNOS in RAW264.7 treated with P.g. LPS. When PKA/PKG pathways were blocked, the suppression of TNF-α, CD86, and iNOS was reversed significantly.

CONCLUSION

Dipyridamole alleviated experimental periodontitis in rat models by regulating M1 polarization via activation of PKA/PKG pathways and emerges as a hopeful remedy for periodontitis.

Advancing stroke therapy: A deep dive into early phase of ischemic stroke and recanalization

Ischemic stroke, accounting for the majority of stroke events, significantly contributes to global morbidity and mortality. Vascular recanalization therapies, namely intravenous thrombolysis and mechanical thrombectomy, have emerged as critical interventions, yet their success hinges on timely application and patient-specific factors. This review focuses on the early phase pathophysiological mechanisms of ischemic stroke and the nuances of recanalization. It highlights the dual role of neutrophils in tissue damage and repair, and the critical involvement of the blood-brain barrier (BBB) in stroke outcomes. Special emphasis is placed on ischemia-reperfusion injury, characterized by oxidative stress, inflammation, and endothelial dysfunction, which paradoxically exacerbates cerebral damage post-revascularization. The review also explores the potential of targeting molecular pathways involved in BBB integrity and inflammation to enhance the efficacy of recanalization therapies. By synthesizing current research, this paper aims to provide insights into optimizing treatment protocols and developing adjuvant neuroprotective strategies, thereby advancing stroke therapy and improving patient outcomes.

Dipyridamole enhances the anti-cancer ability of aspirin against colorectal cancer by inducing apoptosis in an unfolded protein response-dependent manner

PURPOSE

Available evidence indicates that dipyridamole enhances the anti-thrombotic effects of aspirin for the prevention of secondary strokes. Aspirin is a well-known non-steroid anti-inflammatory drug. This anti-inflammatory property has turned aspirin into a potential drug for inflammation-related cancers such as colorectal cancer (CRC). Here, we aimed to explore whether the anti-cancer effect of aspirin against CRC could be improved by combined administration with dipyridamole.

METHODS

Population-based clinical data analysis was conducted to assess a possible therapeutic effect of combined dipyridamole and aspirin treatment in inhibiting CRC compared with either monotherapy. This therapeutic effect was further verified in different CRC mouse models, i.e. an orthotopic xenograft mouse model, an AOM/DSS mouse model, an Apcmin/+ mouse model and a patient derived xenograft (PDX) mouse model. The in vitro effects of the drugs on CRC cells were tested using CCK8 and flow cytometry assays. RNA-Seq, Western blotting, qRT-PCR and flow cytometry were used to identify the underlying molecular mechanisms.

RESULTS

We found that dipyridamole combined with aspirin had a better inhibitory effect on CRC than either monotherapy alone. The enhanced anti-cancer effect of the combined use of dipyridamole with aspirin was found to rely on the induction of an overwhelmed endoplasmic reticulum (ER) stress and subsequent pro-apoptotic unfolded protein response (UPR), which was different from the anti-platelet effect.

CONCLUSIONS

Our data indicate that the anti-cancer effect of aspirin against CRC may be enhanced by combined administration with dipyridamole. In case further clinical studies confirm our findings, these may be repurposed as adjuvant agents.

Potential Therapeutic Benefits of Dipyridamole in COVID-19 Patients

BACKGROUND

COVID-19 pandemic is caused by coronavirus also known as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The viral infection continues to impact the globe with no vaccine to prevent the infection or highly effective therapeutics to treat the millions of infected people around the world. The disease starts as a respiratory infection, yet it may also be associated with a hypercoagulable state, severe inflammation owing to excessive cytokines production, and a potentially significant oxidative stress. The disease may progress to multiorgan failure and eventually death.

OBJECTIVE

In this article, we summarize the potential of dipyridamole as an adjunct therapy for COVID-19.

METHODS

We reviewed the literature describing the biological activities of dipyridamole in various settings of testing. Data were retrieved from PubMed, SciFinder-CAS, and Web of Science. The review concisely covered relevant studies starting from 1977.

RESULTS

Dipyridamole is an approved antiplatelet drug, that has been used to prevent stroke, among other indications. Besides its antithrombotic activity, the literature indicates that dipyridamole also promotes a host of other biological activities including antiviral, anti-inflammatory, and antioxidant ones.

CONCLUSION

Dipyridamole may substantially help improve the clinical outcomes of COVID-19 treatment. The pharmacokinetics profile of the drug is well established which makes it easier to design an appropriate therapeutic course. The drug is also generally safe, affordable, and available worldwide. Initial clinical trials have shown a substantial promise for dipyridamole in treating critically ill COVID-19 patients, yet larger randomized and controlled trials are needed to confirm this promise.

Role of NF-κB in Platelet Function

Platelets are megakaryocyte-derived fragments lacking nuclei and prepped to maintain primary hemostasis by initiating blood clots on injured vascular endothelia. Pathologically, platelets undergo the same physiological processes of activation, secretion, and aggregation yet with such pronouncedness that they orchestrate and make headway the progression of atherothrombotic diseases not only through clot formation but also via forcing a pro-inflammatory state. Indeed, nuclear factor-κB (NF-κB) is largely implicated in atherosclerosis and its pathological complication in atherothrombotic diseases due to its transcriptional role in maintaining pro-survival and pro-inflammatory states in vascular and blood cells. On the other hand, we know little on the functions of platelet NF-κB, which seems to function in other non-genomic ways to modulate atherothrombosis. Therein, this review will resemble a rich portfolio for NF-κB in platelets, specifically showing its implications at the levels of platelet survival and function. We will also share the knowledge thus far on the effects of active ingredients on NF-κB in general, as an extrapolative method to highlight the potential therapeutic targeting of NF-κB in coronary diseases. Finally, we will unzip a new horizon on a possible extra-platelet role of platelet NF-κB, which will better expand our knowledge on the etiology and pathophysiology of atherothrombosis.

[Oxidative stress and inflammation as links in a chain in patients with chronic cerebrovascular diseases]

Cerebrovascular diseases (CVD) are the main cause of death and permanent disability. The urgency of the problem of chronic CVD is associated with an increase of the absolute number of elderly and senile age in the population, a trend towards slowly increasing, sluggish pathological processes. It is obvious that any somatic disease in such patients is comorbid to cerebrovascular diseases that suggests a unified mechanism of the pathogenesis for both the main and concomitant diseases. The article notes that microangiopathy is the most common cause of CVD. The main etiopathogenetic factor affecting cerebral vessels of small caliber is endothelial dysfunction, systemic inflammation and oxidative stress. Understanding the molecular components that underlie functional abnormalities and damage of small blood vessels gives the key to the modern strategies in therapy, forming the foundation for an adequate pathogenetically justified therapy. This impact should be gradual, complex and aimed at correcting pathochemical disorders in general and neurotransmitter imbalance in particular. The drug dipyridamole, which has pleiotropic effects, can be considered as one of the pathogenetically justified means in complex drug therapy in patients with CVD.

Hints on transcriptional control of essential players in heterotopic ossification of Fibrodysplasia Ossificans Progressiva

Signaling of the Bone Morphogenetic Protein (BMP) pathway is influenced by the level of expression of its components, in particular receptors, intracellular molecules and target genes which largely depends on gene transcription. One peculiar aspect of Fibrodysplasia Ossificans Progressiva (FOP) relates to the cell types in which the genetic mutation exerts its effects, then not only those involved in the heterotopic ossification processes but also others that participate in the inflammatory phases preceding and triggering heterotopic ossification. Such effects are in part detectable as variation in gene expression, which is also variably manifesting in term of time of appearance in different phases of the inflammatory or ossification processes.

Effect of Multi Drug Resistance Protein 4 (MRP4) Inhibition on the Pharmacokinetics and Pharmacodynamics of Ciprofloxacin in Normal and Rats with LPS-Induced Inflammation

BACKGROUND AND OBJECTIVES

Infection and inflammation are known to cause wide variability in disposition of drugs through modulation of drug transporters. However, the effects of inhibition of multidrug resistance protein 4 (MRP4) on pharmacokinetics and pharmacodynamics are poorly understood in normal and inflamed conditions. We hypothesized that inflammation alters the pharmacokinetic parameters of ciprofloxacin; and Pharmacokinetic/Pharmacodynamic indices, such as ratio of peak plasma concentration to minimum inhibitory concentration (C _max/MIC) and ratio of area under the plasma drug concentration-time curve to minimum inhibitory concentration (AUC/MIC) of ciprofloxacin will be improved with the co-administration of a MRP4 inhibitor, dipyridamole, in inflammatory conditions.

METHODS

In this study, the role of MRP4 on the pharmacokinetic and pharmacodynamic parameters of ciprofloxacin was investigated by the co-administration of dipyridamole in rats with or without lipopolysaccharide (LPS)-induced inflammation. The pharmacokinetic parameters for ciprofloxacin were calculated by non-compartmental approach. MIC of ciprofloxacin was determined using broth microdilution technique.

RESULTS

Induction of inflammation in rats resulted in marked reduction in C _max and AUC; and an increase in the volume of distribution (V _d/F) and clearance (Cl/F) of ciprofloxacin, compared to normal rats. Co-administration of dipyridamole with ciprofloxacin in inflamed rats resulted in a threefold increase in AUC, a twofold decrease in V _d/F and a threefold decrease in Cl/F of ciprofloxacin with significantly prolonged half-life compared to inflamed rats who received ciprofloxacin alone. Co-administration of dipyridamole enhanced AUC/MIC values of ciprofloxacin in both normal and inflamed rats.

CONCLUSIONS

The results suggest that MRP4 inhibition increases the systemic exposure of ciprofloxacin in both normal and inflammatory conditions.

Ursolic acid reduces the metalloprotease/anti-metalloprotease imbalance in cerebral ischemia and reperfusion injury

BACKGROUND

Activators of PPARs, particularly PPARγ, may be effective neuroprotective drugs against inflammatory responses in cerebral ischemia and reperfusion injury. Ursolic acid (UA) may act as a PPARγ agonist and serve as an anti-inflammatory agent. In this study, we used a rat middle cerebral artery occlusion and reperfusion model to examine how UA acts as a neuroprotective agent to modulate the metalloprotease/anti-metalloprotease balance.

METHODS

The middle cerebral artery occlusion and reperfusion model (occlusion for 2 hours followed by reperfusion for 48 hours) was induced in male Sprague Dawley rats. UA was administered intragastrically 0.5, 24, and 47 hours after reperfusion. Bisphenol A diglycidyl ether (a PPARγ antagonist) was intraperitoneally administered 1, 24.5, and 47.5 hours after reperfusion. Forty-eight hours after reperfusion, neurological deficits and infarct volume were estimated. The PPARγ level and the metalloprotease/anti-metalloprotease balance were examined by Western blotting and immunohistochemistry. The activation of MAPK signaling pathways was also assessed.

RESULTS

UA-treated (5, 10, or 20 mg/kg) rats showed significant improvement in neurological deficit score, infarct volume, and the number of intact neurons compared with control rats (P<0.01). Both the PPARγ protein level and the percentage of PPARγ-positive cells were increased in the UA-treated groups (P<0.01). Compared with the control group, the UA-treated groups exhibited reduced protein levels of MMP2, MMP9, and activated MAPKs (P<0.01) but an increased level of TIMP1 (P<0.01). UA exerted its protective effects in a dose-dependent manner. Co-treatment with UA and bisphenol A diglycidyl ether completely abolished the UA-induced changes in PPARγ expression; however UA continued to exert a significant but partial neuroprotective effect.

CONCLUSION

UA can act as a PPARγ agonist to improve the metalloprotease/anti-metalloprotease balance, possibly by inhibiting the activation of the MAPK signaling pathway, thereby attenuating cerebral ischemia and reperfusion injury. Therefore, UA may serve as a novel neuroprotective therapeutic agent.

High-throughput screening for modulators of ACVR1 transcription: discovery of potential therapeutics for fibrodysplasia ossificans progressiva

The ACVR1 gene encodes a type I receptor of bone morphogenetic proteins (BMPs). Activating mutations in ACVR1 are responsible for fibrodysplasia ossificans progressiva (FOP), a rare disease characterized by congenital toe malformation and progressive heterotopic endochondral ossification leading to severe and cumulative disability. Until now, no therapy has been available to prevent soft-tissue swelling (flare-ups) that trigger the ossification process. With the aim of finding a new therapeutic strategy for FOP, we developed a high-throughput screening (HTS) assay to identify inhibitors of ACVR1 gene expression among drugs already approved for the therapy of other diseases. The screening, based on an ACVR1 promoter assay, was followed by an in vitro and in vivo test to validate and characterize candidate molecules. Among compounds that modulate the ACVR1 promoter activity, we selected the one showing the highest inhibitory effect, dipyridamole, a drug that is currently used as a platelet anti-aggregant. The inhibitory effect was detectable on ACVR1 gene expression, on the whole Smad-dependent BMP signaling pathway, and on chondrogenic and osteogenic differentiation processes by in vitro cellular assays. Moreover, dipyridamole reduced the process of heterotopic bone formation in vivo. Our drug repositioning strategy has led to the identification of dipyridamole as a possible therapeutic tool for the treatment of FOP. Furthermore, our study has also defined a pipeline of assays that will be useful for the evaluation of other pharmacological inhibitors of heterotopic ossification.

Summary: We describe the identification of dipyridamole as a potential therapeutic tool for FOP, through a series of in vitro and in vivo assays to screen and validate FDA-approved compounds.

Therapeutic potential of the dual peroxisome proliferator activated receptor (PPAR)α/γ agonist aleglitazar in attenuating TNF-α-mediated inflammation and insulin resistance in human adipocytes

Adipose tissue inflammation is a mechanistic link between obesity and its related sequelae, including insulin resistance and type 2 diabetes. Dual ligands of peroxisome proliferator activated receptor (PPAR)α and γ, combining in a single molecule the metabolic and inflammatory-regulatory properties of α and γ agonists, have been proposed as a promising therapeutic strategy to antagonize adipose tissue inflammation. Here we investigated the effects of the dual PPARα/γ agonist aleglitazar on human adipocytes challenged with inflammatory stimuli. Human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes were treated with aleglitazar or - for comparison - the selective agonists for PPARα or γ fenofibrate or rosiglitazone, respectively, for 24h before stimulation with TNF-α. Aleglitazar, at concentrations as low as 10nmol/L, providing the half-maximal transcriptional activation of both PPARα and PPARγ, reduced the stimulated expression of several pro-inflammatory mediators including interleukin (IL)-6, the chemokine CXC-L10, and monocyte chemoattractant protein (MCP)-1. Correspondingly, media from adipocytes treated with aleglitazar reduced monocyte migration, consistent with suppression of MCP-1 secretion. Under the same conditions, aleglitazar also reversed the TNF-α-mediated suppression of insulin-stimulated ser473 Akt phosphorylation and decreased the TNF-α-induced ser312 IRS1 phosphorylation, two major switches in insulin-mediated metabolic activities, restoring glucose uptake in insulin-resistant adipocytes. Such effects were similar to those obtainable with a combination of single PPARα and γ agonists. In conclusion, aleglitazar reduces inflammatory activation and dysfunction in insulin signaling in activated adipocytes, properties that may benefit diabetic and obese patients. The effect of aleglitazar was consistent with dual PPARα and γ agonism, but with no evidence of synergism.

Computational drug repositioning for peripheral arterial disease: prediction of anti-inflammatory and pro-angiogenic therapeutics

Peripheral arterial disease (PAD) results from atherosclerosis that leads to blocked arteries and reduced blood flow, most commonly in the arteries of the legs. PAD clinical trials to induce angiogenesis to improve blood flow conducted in the last decade have not succeeded. We have recently constructed PADPIN, protein-protein interaction network (PIN) of PAD, and here we combine it with the drug-target relations to identify potential drug targets for PAD. Specifically, the proteins in the PADPIN were classified as belonging to the angiome, immunome, and arteriome, characterizing the processes of angiogenesis, immune response/inflammation, and arteriogenesis, respectively. Using the network-based approach we predict the candidate drugs for repositioning that have potential applications to PAD. By compiling the drug information in two drug databases DrugBank and PharmGKB, we predict FDA-approved drugs whose targets are the proteins annotated as anti-angiogenic and pro-inflammatory, respectively. Examples of pro-angiogenic drugs are carvedilol and urokinase. Examples of anti-inflammatory drugs are ACE inhibitors and maraviroc. This is the first computational drug repositioning study for PAD.

Classical and pleiotropic actions of dipyridamole: Not enough light to illuminate the dark tunnel?

Dipyridamole is a platelet inhibitor indicated for the secondary prevention of transient ischemic attack. It inhibits the enzyme phosphodiesterase, elevates cAMP and cGMP levels and prevents platelet aggregation. Dipyridamole inhibits the cellular uptake of adenosine into red blood cells, platelets and endothelial cells that results in increased extracellular availability of adenosine, leading to modulation of cardiovascular function. The antiplatelet action of dipyridamole might offer therapeutic benefits in secondary stroke prevention in combination with aspirin. Inflammation and oxidative stress play an important role in atherosclerosis and thrombosis development, leading to stroke progression. Studies demonstrated anti-inflammatory, anti-oxidant and anti-proliferative actions of dipyridamole. These pleiotropic potentials of dipyridamole might contribute to improved therapeutic outcomes when used with aspirin in preventing secondary stroke. Dipyridamole was documented as a coronary vasodilator 5 decades ago. The therapeutic failure of dipyridamole as a coronary vasodilator is linked with induction of 'coronary steal' phenomenon in which by dilating resistance vessels in non-ischemic zone, dipyridamole diverts the already reduced blood flow away from the area of ischemic myocardium. Dipyridamole at high-dose could cause a marked 'coronary steal' effect. Dipyridamole, however, at low-dose could have a minimal hemodynamic effect. Low-dose dipyridamole treatment has a therapeutic potential in partially preventing diabetes mellitus-induced experimental vascular endothelial and renal abnormalities by enhancing endothelial nitric oxide signals and inducing renovascular reduction of oxidative stress. In spite of plenteous research on dipyridamole's use in clinics, its precise clinical application is still obscure. This review sheds lights on pleiotropic pharmacological actions and therapeutic potentials of dipyridamole.

Rapamycin alleviates brain edema after focal cerebral ischemia reperfusion in rats

Brain edema is a major consequence of cerebral ischemia reperfusion. However, few effective therapeutic options are available for retarding the brain edema progression after cerebral ischemia. Recently, rapamycin has been shown to produce neuroprotective effects in rats after cerebral ischemia reperfusion. Whether rapamycin could alleviate this brain edema injury is still unclear. In this study, the rat stroke model was induced by a 1-h left transient middle cerebral artery occlusion using an intraluminal filament, followed by 48 h of reperfusion. The effects of rapamycin (250 μg/kg body weight, intraperitoneal; i.p.) on brain edema progression were evaluated. The results showed that rapamycin treatment significantly reduced the infarct volume, the water content of the brain tissue and the Evans blue extravasation through the blood-brain barrier (BBB). Rapamycin treatment could improve histological appearance of the brain tissue, increased the capillary lumen space and maintain the integrity of BBB. Rapamycin also inhibited matrix metalloproteinase 9 (MMP9) and aquaporin 4 (AQP4) expression. These data imply that rapamycin could improve brain edema progression after reperfusion injury through maintaining BBB integrity and inhibiting MMP9 and AQP4 expression. The data of this study provide a new possible approach for improving brain edema after cerebral ischemia reperfusion by administration of rapamycin.

Pterygium: nonsurgical treatment using topical dipyridamole - a case report

Purpose

We report a case of a symptomatic, inflamed pterygium treated nonsurgically with topical dipyridamole and followed for 12 months.

Case Report

A 35-year-old woman presented with a stage II to III, V3, C3, K2, P1 (using Johnston, Williams & Sheppard's classification) pterygium in her right eye. She complained of a foreign body sensation, dryness, burning, and persistent uncontrolled blinking. A raised lesion was observed on the nasal conjunctiva that was 1.5 mm in size. It extended slightly onto the nasal cornea. There was moderate vascularity of the lesion that obscured the underlying scleral vessels. Moderate conjunctival hyperemia was detected at and medial to the pterygium. The cornea, anterior chamber, and external anatomy were otherwise unremarkable. The eye was initially treated twice daily with a topical application of dipyridamole in a normal saline solution, which was later reduced to once daily.

Results

There was a marked improvement in both the pterygium and the patient's symptoms. The tissue regressed from the limbal region of the cornea, had decreased in length from 1.5 to 1.0 mm, and decreased in height from approximately 1.0 to approximately 0.3 mm. Conjunctival hyperemia and vascularization resolved completely, and the underlying scleral vessels could once again be visualized. At 12 months, the pterygium was graded as stage 0 to I, V0, C2, K0, P0.

Conclusions

To our knowledge, this is the first case of successful management of a pterygium and associated symptoms using topical dipyridamole. Further investigation is required to clarify the potential role of dipyridamole in the treatment of pterygia and pingueculae.