CRP Is a Key Indicator of Rheumatoid Arthritis-Associated Vascular Injury and Neurodegeneration.

Systemic inflammation plays a pivotal role in the progression of rheumatoid arthritis (RA) and its associated comorbidities, ranging from cardiovascular (CV) disease to neurodegenerative conditions such as Alzheimer's disease (AD). This narrative review examines the molecular cross-talk linking these pathologies, with a specific focus on the distinction between pentameric C-reactive protein (pCRP) and its proinflammatory monomeric form (mCRP). We discuss evidence suggesting that mCRP is not merely a passive marker but also an active driver of endothelial dysfunction, atherosclerosis, and synovial inflammation. This review further explores the connections among inflammatory biomarkers, blood vessel integrity, and neurodegeneration, detailing how persistent cytokine elevation (IL-6, TNF-α) and vascular injury contribute to cerebral small vessel disease (cSVD) and cognitive decline, with neurofilament light chain (NfL) serving as a key biomarker of neuroaxonal injury. Additionally, we address the neurobiology of pain in RA, highlighting the mechanisms of central sensitization (CS) and neuroimmune signalling that sustain pain-independent joint swelling. This evidence indicates that understanding the dynamic connection between CRP isoforms and neuronal markers should offer new insights for risk stratification and suggests that targeting mCRP may provide a novel therapeutic avenue to mitigate both articular and extra-articular manifestations of RA.