What if chronic fatigue, anxiety, and accelerated aging share a common biological root — not in the brain itself, but in a signaling molecule released when cells cannot meet their energy demands? A newly proposed framework centered on the cytokine GDF15 reframes these seemingly disparate phenomena as outputs of a coherent interoceptive system, with significant implications for understanding mental health, resilience, and longevity.
The framework, termed "mitoception," describes a two-arm signaling cascade. The afferent arm is triggered when mitochondrial energy transformation capacity falls short of cellular demand — an "energy gap" — activating the integrated stress response and releasing GDF15 into circulation. The efferent arm operates when GDF15 binds to receptors in the brainstem's GFRAL (glial cell-derived neurotrophic factor family receptor alpha-like) system, producing subjective experiences of fatigue and anxiety while simultaneously initiating neuroendocrine stress responses and redistributing fuel toward survival-critical processes. The authors characterize this loop as a brain-directed metabolic triage system — one that shapes mood, healing trajectories, and putatively the rate of biological aging.
GDF15 has attracted substantial scientific attention over the past decade primarily in the contexts of cancer cachexia, exercise physiology, and caloric restriction — metformin, for instance, is known to elevate GDF15 levels, which may partly explain its appetite-suppressing effects. What this conceptual paper adds is an integrative psychobiological interpretation: that GDF15 is not merely a stress biomarker but a functional mediator connecting mitochondrial status to psychological state and systemic allostasis. The framework is theoretically rich but remains largely speculative; the article is explicitly an introduction to a new model rather than a report of original empirical data. Key predictions about modifiable lifestyle factors — including sleep, exercise, and psychosocial stress — shaping the mitoception cascade remain to be tested in controlled human trials. If validated, this could reposition GDF15 as a central target for interventions aimed at fatigue syndromes, mood disorders, and healthspan extension.
