Neutrophil degranulation, endothelial and metabolic dysfunction in unvaccinated long COVID patients.

BACKGROUND: Long COVID symptoms are widely diffused and have a poorly understood pathophysiology, with possible involvement of inflammatory cytokines. MATERIALS AND METHODS: A prospective follow-up study involved 385 unvaccinated patients, started 1 month after SARS-CoV-2 infection and continued for up to 12 months. We compared circulating biomarkers of neutrophil degranulation, endothelial and metabolic dysfunction in subjects with long COVID symptoms and in asymptomatic post-COVID controls. RESULTS: The highest occurrence of symptoms (71%) was after 3 months from the infection, decreasing to 62.3% and 29.4% at 6 and 12 months, respectively. Compared to controls, long COVID patients had increased levels of the neutrophilic degranulation indices MMP-8 and MPO, of endothelial dysfunction indices L-selectin and P-selectin. Among indices of metabolic dysfunction, leptin levels were higher in long COVID patients than in controls. CONCLUSION: In unvaccinated patients, symptoms may persist up to 1 year after acute COVID infection, with increased indices of neutrophil degranulation, endothelial and metabolic dysfunction. The clinical implications of specific inflammatory biomarkers require further attention, especially in individuals with fatigue and long COVID-linked cognitive dysfunctions.

The Potential of the Mediterranean Diet to Improve Mitochondrial Function in Experimental Models of Obesity and Metabolic Syndrome.

The abnormal expansion of body fat paves the way for several metabolic abnormalities including overweight, obesity, and diabetes, which ultimately cluster under the umbrella of metabolic syndrome (MetS). Patients with MetS are at an increased risk of cardiovascular disease, morbidity, and mortality. The coexistence of distinct metabolic abnormalities is associated with the release of pro-inflammatory adipocytokines, as components of low-to-medium grade systemic inflammation and increased oxidative stress. Adopting healthy lifestyles, by using appropriate dietary regimens, contributes to the prevention and treatment of MetS. Metabolic abnormalities can influence the function and energetic capacity of mitochondria, as observed in many obesity-related cardio-metabolic disorders. There are preclinical studies both in cellular and animal models, as well as clinical studies, dealing with distinct nutrients of the Mediterranean diet (MD) and dysfunctional mitochondria in obesity and MetS. The term "Mitochondria nutrients" has been adopted in recent years, and it depicts the adequate nutrients to keep proper mitochondrial function. Different experimental models show that components of the MD, including polyphenols, plant-derived compounds, and polyunsaturated fatty acids, can improve mitochondrial metabolism, biogenesis, and antioxidant capacity. Such effects are valuable to counteract the mitochondrial dysfunction associated with obesity-related abnormalities and can represent the beneficial feature of polyphenols-enriched olive oil, vegetables, nuts, fish, and plant-based foods, as the main components of the MD. Thus, developing mitochondria-targeting nutrients and natural agents for MetS treatment and/or prevention is a logical strategy to decrease the burden of disease and medications at a later stage. In this comprehensive review, we discuss the effects of the MD and its bioactive components on improving mitochondrial structure and activity.