Fluctuations in depression and anxiety predict dysregulated leptin among obese breast cancer survivors

Metabolic underpinnings of cancer-related fatigue

Cancer-related fatigue (CRF) is one of the most prevalent and detrimental complications of cancer. Emerging evidence suggests that obesity and insulin resistance are associated with CRF occurrence and severity in cancer patients and survivors. In this narrative review, we analyzed recent studies including both preclinical and clinical research on the relationship between obesity and/or insulin resistance and CRF. We also describe potential mechanisms for these relationships, though with the caveat that because the mechanisms underlying CRF are incompletely understood, the mechanisms mediating the association between obesity/insulin resistance and CRF are similarly incompletely delineated. The data suggest that, in addition to their effects to worsen CRF by directly promoting tumor growth and metastasis, obesity and insulin resistance may also contribute to CRF by inducing chronic inflammation, neuroendocrinological disturbance, and metabolic alterations. Furthermore, studies suggest that patients with obesity and insulin resistance experience more cancer-induced pain and are at more risk of emotional and behavioral disruptions correlated with CRF. However, other studies implied a potentially paradoxical impact of obesity and insulin resistance to reduce CRF symptoms. Despite the need for further investigation utilizing interventions to directly elucidate the mechanisms of cancer-related fatigue, current evidence demonstrates a correlation between obesity and/or insulin resistance and CRF, and suggests potential therapeutics for CRF by targeting obesity and/or obesity-related mediators.

A review and novel theoretical model of how negative emotions influence inflammation: The critical role of emotion regulation

Psychological distress is an inevitable part of life. Research drawing on theories from clinical psychology, health psychology, and psychoneuroimmunology (PNI) has identified relationships between negative emotions such as anxiety and sadness with inflammation. When not regulated properly, negative emotions can create biological wear and tear on the body that can increase risk for morbidity and mortality. This review discusses previously available research on relationships between negative emotions and emotion regulation with inflammation among both physically healthy adults and those with chronic illnesses. I then present a novel comprehensive biobehavioral model of negative emotionality. This model emphasizes the influence of negative emotions and their contribution to heightened inflammation. Further, I also discuss how emotion regulation (including perseverative processes such as worry and rumination) mediates this association. The relationships between negative emotionality and emotion regulation may be bidirectional, and empirical investigation of this model should specifically seek to disentangle these relationships. The proposed model offers the opportunity to advance PNI research through understanding how emotional factors alter inflammation and contribute to accelerated biological aging and disease risk.