Pentoxifylline as a Potential Adjuvant Therapy for COVID-19: Impeding the Burden of the Cytokine Storm

Clinicopathologic Analysis of COVID‐19 Associated Thrombi in the Setting of Large Vessel Occlusion: A Prospective Case–Control Study

BACKGROUND

Acute ischemic stroke secondary to large vessel occlusion is among the most serious complications associated with COVID‐19 infection resulting in worse morbidity and mortality. We sought to study the association between COVID‐19 infection and large vessel occlusion thrombus pathology to better define the etiopathogenesis of this atypical cause of stroke.

METHODS

Thrombi were collected during mechanical thrombectomy and stained using hematoxylin and eosin. Blinded analysis of pathology was prospectively performed by a board‐certified neuropathologist. Red blood cell, fibrin, and white blood cell predominance was ascertained. Concomitant peripheral blood counts and clinical and imaging data were collected and analyzed. All samples underwent performance of reverse transcription polymerase chain reaction for SARS‐CoV2.

RESULTS

Between January 2020 and February 2022, a total of 952 acute ischemic stroke admissions were seen at the University Medical Center of El Paso, TX. Of these, 195 patients (20.5%) had large vessel occlusions and underwent mechanical thrombectomy and 53 patients had thrombus collected and analyzed. Seven patients (3.6%) tested positive for SARS‐CoV2. COVID‐19 positive patients were more likely to be younger (mean 57.4 years; P =0.07), male (85.7%; P =0.03), and have red blood cell predominant thrombi (85.7%; P =0.03). There was a statistically significant association between peripheral neutrophil count and white blood cell lysis in the overall cohort ( P =0.015), who did not differ according to COVID‐19 status.

CONCLUSION

Thrombi retrieved from patients who were COVID‐19 positive and had stroke demonstrated red blood cell predominance. This finding requires further investigation using appropriate immunohistochemical techniques in a larger cohort of patients.

Pentoxifylline Effects on Hospitalized COVID-19 Patients with Cytokine Storm Syndrome: A Randomized Clinical Trial

COVID-19 is a fatal, fast-spreading pandemic, and numerous attempts are being made around the world to understand and manage the disease. COVID-19 patients may develop a cytokine-release syndrome, which causes serious respiratory diseases and, in many cases, death. The study examined the feasibility of employing legally available anti-inflammatory pentoxifylline (PTX), a low toxicity and cost medication, to mitigate the hyper-inflammation caused by COVID-19. Thirty adult patients who tested positive for SARS-CoV2 were hospitalized owing to the cytokine storm syndrome. They were given 400 mg of pentoxifylline orally TID according to the standard COVID-19 protocol of the Egyptian Ministry of Health. Besides this, a group of thirty-eight hospitalized COVID-19 patients who received the standard COVID-19 protocol was included in the study as a control group. The outcomes included laboratory test parameters, clinical improvements, and number of deaths in both groups. After receiving PTX, all patients showed a significant improvement in C reactive protein (CRP), and interleukin-6 (IL-6) levels at p < 0.01 and p = 0.004, respectively, while there was an increase in total leukocyte count (TLC) and neutrophil-to-leucocyte ratio (NLR) at p < 0.01 compared to their baseline levels. The D-dimer level showed a significant increase in the treatment group at p < 0.01, while showing no statistically significant difference in the control group. The median initial ALT (42 U/L) in the treatment group showed a decrease compared to the control group (51 U/L). No statistical significance was reported regarding clinical improvement, length of stay, and death percentages between the two groups. Our results showed no significant improvement of PTX over controls in clinical outcomes of hospitalized COVID-19 patients. Nevertheless, PTX displayed a positive effect on certain inflammatory biomarkers.

Therapeutic considerations for prevention and treatment of thrombotic events in COVID-19

Thrombosis is a known complication of SARS-CoV-2 infection, particularly within a severely symptomatic subset of patients with COVID-19 disease, in whom an aggressive host immune response leads to cytokine storm syndrome (CSS). The incidence of thrombotic events coinciding with CSS may contribute to the severe morbidity and mortality observed in association with COVID-19. This review provides an overview of pharmacologic approaches based upon an emerging understanding of the mechanisms responsible for thrombosis across a spectrum of COVID-19 disease involving an interplay between immunologic and pro-thrombotic events, including endothelial injury, platelet activation, altered coagulation pathways, and impaired fibrinolysis.

The role of oxidative stress in the pathogenesis of infections with coronaviruses

Coronaviruses can cause serious respiratory tract infections and may also impact other end organs such as the central nervous system, the lung and the heart. The coronavirus disease 2019 (COVID-19) has had a devastating impact on humanity. Understanding the mechanisms that contribute to the pathogenesis of coronavirus infections, will set the foundation for development of new treatments to attenuate the impact of infections with coronaviruses on host cells and tissues. During infection of host cells, coronaviruses trigger an imbalance between increased production of reactive oxygen species (ROS) and reduced antioxidant host responses that leads to increased redox stress. Subsequently, increased redox stress contributes to reduced antiviral host responses and increased virus-induced inflammation and apoptosis that ultimately drive cell and tissue damage and end organ disease. However, there is limited understanding how different coronaviruses including SARS-CoV-2, manipulate cellular machinery that drives redox responses. This review aims to elucidate the redox mechanisms involved in the replication of coronaviruses and associated inflammation, apoptotic pathways, autoimmunity, vascular dysfunction and tissue damage that collectively contribute to multiorgan damage.