Stress levels, psychological symptoms, and C-reactive protein levels in COVID-19: A cross-sectional study

Monomeric C-reactive protein as a biomarker for major depressive disorder

Neuroinflammation has been postulated to be a key factor in the pathogenesis of major depressive disorder (MDD). With this is mind, there has been a wave of research looking into pro-inflammatory mediators as potential biomarkers for MDD. One such mediator is the acute phase protein, C-reactive protein (CRP). While several studies have investigated the potential of CRP as a biomarker for MDD, the results have been inconsistent. One explanation for the lack of consistent findings may be that the high-sensitivity CRP tests utilized in these studies only measure the pentameric isoform of CRP (pCRP). Recent research, however, has indicated that the monomeric isoform of CRP (mCRP) is responsible for the pro-inflammatory function of CRP, while pCRP is weakly anti-inflammatory. The objective of this minireview is to re-examine the evidence of CRP involvement in MDD with a view of mCRP as a potential biomarker.

COVID-19, Anxiety, and Body Mass Index Increase Leptin Levels: a Cross-sectional Multicentric Study

Although many efforts have been made to understand the pathophysiological mechanisms of COVID-19, critical gaps remain to be explored. This study aimed to investigate potential alterations in adipokine levels (specifically adiponectin, leptin, and resistin) among individuals with COVID-19. Within this population, we further assessed the association between these markers with both, body mass index (BMI) and psychiatric symptoms. This cross-sectional study included an age- and sex-matched sample of adults with COVID-19 (cases) and without COVID-19 (controls). We evaluated the severity of psychiatric symptoms, BMI, and adipokines. Individuals with COVID-19 presented greater BMI, stress levels, and leptin levels when compared to controls. Leptin levels were greater in individuals with moderate/severe COVID-19 as compared to individuals with COVID-19 who were asymptomatic or having mild symptoms. Leptin levels were positively correlated with BMI, severity of depressive and anxiety symptoms, and stress levels in the total sample. Leptin levels were also positively correlated with BMI, severity of anxiety symptoms, and stress levels in controls. In cases, there was a positive correlation between adiponectin and the severity of depressive symptoms and stress levels and leptin/resistin with BMI. A linear regression model revealed that BMI, severity of anxiety symptoms, and the diagnosis of COVID-19 are independently associated with increased leptin levels. Thus, leptin levels seem to be impacted by the COVID-19 infection, anxiety, and BMI.

Major depressive disorder as a neuro-immune disorder: Origin, mechanisms, and therapeutic opportunities

Notwithstanding advances in understanding the pathophysiology of major depressive disorder (MDD), no single mechanism can explain all facets of this disorder. An expanding body of evidence indicates a putative role for the inflammatory response. Several meta-analyses showed an increase in systemic peripheral inflammatory markers in individuals with MDD. Numerous conditions and circumstances in the modern world may promote chronic systemic inflammation through mechanisms, including alterations in the gut microbiota. Peripheral cytokines may reach the brain and contribute to neuroinflammation through cellular, humoral, and neural pathways. On the other hand, antidepressant drugs may decrease peripheral levels of inflammatory markers. Anti-inflammatory drugs and nutritional strategies that reduce inflammation also could improve depressive symptoms. The present study provides a critical review of recent advances in the role of inflammation in the pathophysiology of MDD. Furthermore, this review discusses the role of glial cells and the main drivers of changes associated with neuroinflammation. Finally, we highlight possible novel neurotherapeutic targets for MDD that could exert antidepressant effects by modulating inflammation.