THERAPEUTIC TARGETING OF BRAIN ARACHIDONIC ACID CASCADE IN BIPOLAR DISORDER BY LOW DOSE ASPIRIN AND CELECOXIB

Challenges and Opportunities for Celecoxib Repurposing

Drug repositioning, also known as drug repurposing, reprofiling, or rediscovery, is considered to be one of the most promising strategies to accelerate the development of new original drug products. Multiple examples of successful rediscovery or therapeutic switching of old molecules that did not show clinical benefits or safety in initial trials encourage the following of the discovery of new therapeutic pathways for them. This review summarizes the efforts that have been made, mostly over the last decade, to identify new therapeutic targets for celecoxib. To achieve this goal, records gathered in MEDLINE PubMed and Scopus databases along with the registry of clinical trials by the US National Library of Medicine at the U.S. National Institutes of Health were explored. Since celecoxib is a non-steroidal anti-inflammatory drug that represents the class of selective COX-2 inhibitors (coxibs), its clinical potential in metronomic cancer therapy, the treatment of mental disorders, or infectious diseases has been discussed. In the end, the perspective of a formulator, facing various challenges related to unfavorable physicochemical properties of celecoxib upon the development of new oral dosage forms, long-acting injectables, and topical formulations, including the latest trends in the pharmaceutical technology, such as the application of mesoporous carriers, biodegradable microparticles, lipid-based nanosystems, or spanlastics, was presented.

Inflammation, Lifestyle Factors, and the Microbiome-Gut-Brain Axis: Relevance to Depression and Antidepressant Action

Depression is considered a major public health concern, where existing pharmacological treatments are not equally effective across all patients. The pathogenesis of depression involves the interaction of complex biological components, such as the immune system and the microbiota-gut-brain axis. Adjunctive lifestyle-oriented approaches for depression, including physical exercise and special diets are promising therapeutic options when combined with traditional antidepressants. However, the mechanisms of action of these strategies are incompletely understood. Accumulating evidence suggests that physical exercise and specific dietary regimens can modulate both the immune system and gut microbiota composition. Here, we review the current information about the strategies to alleviate depression and their crosstalk with both inflammatory mechanisms and the gut microbiome. We further discuss the role of the microbiota-gut-brain axis as a possible mediator for the adjunctive therapies for depression through inflammatory mechanisms. Finally, we review existing and future adjunctive strategies to manipulate the gut microbiota with potential use for depression, including physical exercise, dietary interventions, prebiotics/probiotics, and fecal microbiota transplantation.

Blood-brain barrier penetrating carbon dots with intrinsic anti-inflammatory and drug-loading properties

The blood-brain barrier (BBB) is the major obstacle limiting the reach of therapeutic drugs into the brain. Herein, an aspirin-based anti-inflammatory replenisher (aspCD) was fabricated by carbonizing aspirin to deliver drugs into the brain visually. The as-prepared aspCD combined the BBB-penetrating and anti-inflammatory effects of aspirin with the fluorescent and drug-loading properties of carbon dots (CDs), thereby delivering therapeutic drugs into the brain and acting as imaging agent as well as anti-inflammatory replenisher. In vivo experiments of mice and zebrafish revealed that fluorescence aspCD could effectively penetrate BBB. In vitro and in vivo inflammatory models demonstrated that aspCD could be regarded as an excellent anti-inflammatory replenisher. In addition, as a functional carrier, aspCD was proved to be capable of loading drugs with different polarity. In summary, carbonization of active precursors (therapeutic drugs) into CDs could be a promising strategy to achieve the loading and visualization of drugs as well as the retainment of their biological activities.

Aspirin and celecoxib may help to rectify a neurotransmission imbalance in bipolar disorder

BACKGROUND

Mood stabilizers with disparate chemical structures are approved for treating bipolar disorder, but their mechanisms of action are not agreed on. However, when administered to unanesthetized rats at clinically relevant doses, they modulate neurotransmission involving arachidonic acid and brain activity of COX-2, which oxidizes arachidonic acid within the arachidonic acid metabolic cascade.

HYPOTHESIS

Inhibiting COX-2 directly might enhance mood stabilizer effects in bipolar disorder patients.

OBSERVATIONS

This paper reviews randomized controlled trials that showed that celecoxib, a selective COX-2 inhibitor, or low-dose aspirin, which inhibits COX-1 and inhibits/acetylates COX-2, reduced bipolar symptoms in patients on mood stabilizers. More convincing are two population based pharmacoepidemiological studies that each demonstrated that chronic low dose aspirin reduced bipolar severity markers in patients on mood stabilizers.

CONCLUSIONS

This clinical evidence is consistent with the hypothesis that low-dose chronic aspirin and celecoxib, which can inhibit COX-2 and enter brain, can be repurposed in bipolar disorder to enhance mood stabilizer effects on arachidonic acid metabolism and neurotransmission.