Does chronic low-grade systemic inflammation contribute to atherosclerosis and vascular aging?

The claim that chronic low-grade systemic inflammation contributes to atherosclerosis and vascular aging is supported by science. Ample clinical and mechanistic evidence confirms that persistent, low-grade sterile inflammation (often termed "inflammaging") is a primary driver of both plaque development and structural arterial stiffening.

Clinical evidence and outcomes

• Atherosclerotic Risk: Elevated systemic inflammation, characterized by high-sensitivity C-reactive protein (hs-CRP) levels $\ge$2 mg/L, is clinically associated with a 1.3- to 2.0-fold increased hazard for major adverse cardiovascular events (MACE), stroke, and coronary heart disease. This risk is independent of traditional lipid levels.
• Arterial Stiffness: High-resolution longitudinal cohort studies show that elevated baseline levels of inflammatory markers (such as hs-CRP and interleukin-6 [IL-6]) independently predict a progressive decline in arterial distensibility and a corresponding increase in pulse wave velocity (PWV) over a 10-year follow-up.

Mechanistic explanations

• The Inflammatory Axis in Atherosclerosis: Modified low-density lipoprotein (LDL) and cholesterol crystals within the arterial intima act as danger-associated molecular patterns (DAMPs) that trigger the NLRP3 inflammasome in macrophages. This leads to caspase-1 activation and the cleavage of pro-IL-1$\beta$ into its active form.
• Systemic Amplification: Active IL-1$\beta$ and TNF-$\alpha$ upregulate adhesion molecules (VCAM-1 and ICAM-1) on endothelial cells, recruiting leukocytes and promoting foam cell formation. Downstream, IL-1$\beta$ induces hepatic IL-6 production, amplifying systemic inflammatory cascades.
• Vascular Aging (Inflammaging): Persistent systemic levels of IL-6, IL-1$\beta$, and TNF-$\alpha$ activate cellular NF-$\kappa$B pathways, prompting endothelial cells and vascular smooth muscle cells (VSMCs) to enter cellular senescence.
• Structural Remodeling & Phenotypic Switching: Senescent vascular cells develop a senescence-associated secretory phenotype (SASP), releasing matrix metalloproteinases (MMPs) that degrade elastin. This is accompanied by TGF-$\beta$-driven collagen deposition and a phenotypic switch in VSMCs from a contractile to an osteogenic state, causing medial calcification and arterial stiffening.

Bottom line

Chronic low-grade systemic inflammation is a major biological catalyst that accelerates both atherosclerosis and vascular aging. It drives plaque progression via the NLRP3/IL-1$\beta$/IL-6 pathway and accelerates arterial stiffening by promoting cellular senescence, matrix remodeling, and osteogenic transitions in vascular smooth muscle cells.