An Update: Exploring the Mechanisms and Clinical Significance of Amyloidosis-associated Neuropathy

Amyloidosis encompasses a spectrum of disorders characterized by the extracellular accumulation of insoluble amyloid fibrils in various tissues, with peripheral neuropathy emerging as one of the most significant clinical manifestations. Peripheral sensory neurons are highly susceptible to amyloid-induced injury due to their long axonal projections and the relatively weaker neurovascular barrier of the dorsal root ganglia compared with the blood-brain and plasma-nerve barriers. Resulting nerve damage contributes to painful and disabling peripheral neuropathy, which affects millions worldwide. While hereditary amyloidosis polyneuropathies and type 2 diabetes are well-recognized conditions linked to amyloid deposition and neuropathy, similar pathogenic mechanisms may also be implicated in certain autoimmune and chronic metabolic disorders. A unifying histopathological feature across these diverse conditions is the deposition of amyloidogenic proteins. These fibrillar aggregates, composed of self-assembled peptides and proteins, disrupt tissue homeostasis, impair cellular function, and promote progressive nerve damage. Both inherited and acquired forms of amyloidosis are capable of triggering neuropathic complications, suggesting that amyloid-related mechanisms represent a convergent pathway in neuropathy of varied etiologies. In particular, type 2 diabetes mellitus stands out as a common condition in which amyloid accumulation significantly contributes to peripheral nerve injury. Collectively, these observations highlight the molecular and cellular parallels between different forms of amyloid-associated neuropathies and emphasize the need for deeper investigation into shared mechanisms that link protein aggregation with neuronal dysfunction.