Comment on Kopanska et al. Disorders of the Cholinergic System in COVID-19 Era-A Review of the Latest Research. Int. J. Mol. Sci. 2022, 23, 672.

We read the recent review article by Marta Kopanska et al. [...].

Can pentoxifylline and similar xanthine derivatives find a niche in COVID-19 therapeutic strategies? A ray of hope in the midst of the pandemic.

COVID-19 pandemic presents an unprecedented challenge to identify effective drugs for treatment. Despite multiple clinical trials using different agents, there is still a lack of specific treatment for COVID-19. Having the potential role in suppressing inflammation, immune modulation, antiviral and improving respiratory symptoms, this review discusses the potential role of methylxanthine drugs like pentoxifylline and caffeine in the management of COVID-19 patients. COVID-19 pathogenesis for clinical features like severe pneumonia, acute lung injury (ALI) / acute respiratory distress syndrome (ARDS), and multi-organ failures are excessive inflammation, oxidation, and cytokine storm by the exaggerated immune response. Drugs like pentoxifylline have already shown improvement of the symptoms of ARDS and caffeine has been in clinical use for decades to treat apnea of prematurity (AOP) in preterm infants and improve respiratory function. Pentoxifylline is well-known anti-inflammatory and anti-oxidative molecules that have already shown to suppress Tumor Necrosis Factor (TNF-α) as well as other inflammatory cytokines in pulmonary diseases, and this may be beneficial for better clinical outcomes in COVID-19 patients. Pentoxifylline enhances blood flow, improves microcirculation and tissue oxygenation, and caffeine also efficiently improves tissue oxygenation, asthma, decreases pulmonary hypertension and an effective analgesic. There are significant shreds of evidence that proved the properties of pentoxifylline and caffeine against virus-related diseases as well. Along with the aforementioned evidences and high safety profiles, both pentoxifylline and caffeine offer a glimpse of considerations for future use as a potential adjuvant to COVID-19 treatment. However, additional clinical studies are required to confirm this speculation.

Rediscovery of Caffeine: An Excellent Drug for Improving Patient Outcomes while Fighting WARS.

The COVID-19 (here specifically called Worldwide Acute Respiratory Syndrome, WARS) pandemic is surging worldwide. Unfortunately, no specific drug meets the urgent need to fight this pandemic, leading to thousands of deaths. The theory of host-directed therapies (HDTs) is viewed as the ideal means to rephrase the treatment of infectious diseases. However, related drugs based on this theory have not been identified. Previously, we realized that caffeine is the ligand of type 2 taste receptors (TAS2Rs), which play a critical role in host defense. Here, we gathered data on caffeine acting as an immunomodulator. Unexpectedly, we found that caffeine can fight WARS by acting on multiple organs, which may prevent the virus from entering the cell, stimulate the phagocytosis of macrophages, enhance breathing, and inhibit the cytokine storm. Thus, the immunoprotective effects of caffeine can improve the therapeutic outcomes in patients infected with coronavirus. Collectively, we report that caffeine, an FDA-approved, highly safe, inexpensive, and widely available drug, could be an excellent HDT for battling WARS.