Why diabetic nerves fail from the feet up: a new review puts damaged mitochondria at the center

Peripheral nerves are among the most energy-hungry structures in the body: a single motor neuron's axon can run a meter, and every centimeter depends on mitochondria delivered, maintained and recycled on site. A review by Wu, Chen and colleagues at the Second Qilu Hospital of Shandong University, published open access on October 17, 2026 in the Journal of Translational Medicine, synthesizes mechanistic, translational and clinical evidence into one claim: mitochondrial dysfunction is not a side effect of diabetic neuropathy but a core pathogenic hub where its causes converge.

How does mitochondrial failure dismantle a nerve fiber?

The review walks a connected chain. High glucose, lipid overload and microvascular stress make the electron transport chain inefficient; leaked electrons form reactive oxygen species that damage mitochondrial DNA (tracked by markers such as 8-OHdG) and membrane lipids. Calcium floods in through the mitochondrial calcium uniporter until the permeability transition pore opens and the energy gradient collapses. Mitochondria fragment excessively, their transport to distant axon tips falters, and mitophagy — the PINK1–Parkin cleanup system — fails, so damaged units accumulate exactly where energy demand is highest: the feet.

What turns energy failure into axon death and pain?

Two execution pathways stand out. When mitochondrial dysfunction drains the cofactor NAD+, the protein SARM1 switches on and degrades what NAD+ remains, triggering a self-destruct program that dismantles the axon. Meanwhile, damaged mitochondria release danger signals that activate the NLRP3 inflammasome and the cGAS–STING pathway, converting energy failure into neuroinflammation and pain sensitization. The authors argue the same mitochondrial signatures recur across painful, painless, corneal and autonomic forms of diabetic neuropathy — different faces of one hub failure.

What treatments does the hub model point to — and how ready are they?

Candidates surveyed include exercise and dietary strategies that drive mitochondrial biogenesis (AMPK–PGC-1alpha), SARM1 inhibitors that block the axon-destruction switch, mitophagy modulators, and mitochondria-targeted antioxidants such as MitoQ and MitoTEMPO, which concentrate where generic antioxidants penetrate poorly. The review is sober about readiness: target engagement is shown mostly in cells, animals and early biomarker studies, human validation is insufficient, nerve-structure endpoints are inconsistently measured, and the narrative review applied no formal GRADE assessment. Current care remains symptom relief plus glucose control — nothing approved repairs the nerve.

Where the evidence stands

• Established: Diabetic neuropathy involves axonal energy failure, oxidative stress and mitochondrial damage; the longest fibers fail first, and no approved therapy modifies the disease — care is symptomatic plus glycemic control.
• Preliminary: A Journal of Translational Medicine review (Oct 17, 2026) integrates evidence that electron-transport inefficiency, calcium overload, fragmentation, failed mitophagy, SARM1/NAD+ axon degeneration and NLRP3/cGAS-STING inflammation form one mitochondrial hub across neuropathy subtypes.
• Absent: High-quality human trials showing any mitochondria-targeted therapy — SARM1 inhibitors, mitophagy modulators or targeted antioxidants — repairs diabetic nerves or changes patient outcomes.