Marked Changes in Serum Amyloid A Distribution and High-Density Lipoprotein Structure during Acute Inflammation

Area of Science:

• Cardiovascular Research
• Lipoprotein Metabolism
• Inflammation Biology

Background:

• High-density lipoprotein (HDL) cholesterol is a key cardiovascular disease marker.
• HDL is heterogeneous and can become dysfunctional during inflammation.
• Understanding rapid HDL remodeling is crucial for assessing cardiovascular risk.

Purpose of the Study:

• To investigate rapid HDL remodeling during acute inflammation post-orthopedic surgery.
• To determine the role of serum amyloid A (SAA) in acute HDL changes.
• To assess the impact of these changes on HDL's atheroprotective functions.

Main Methods:

• Analysis of HDL from 13 orthopedic surgery patients (preoperative and POD 1-7).
• Quantification of SAA, apolipoprotein A-I (apoA-I), and apolipoprotein A-II (apoA-II).
• Assessment of HDL particle size, surface charge, and protein distribution using electrophoresis and chromatography.

Main Results:

• Plasma SAA peaked on postoperative day 3 (POD3).
• HDL showed a decreased apoA-I:apoA-II ratio and loss of small particles on POD3.
• HDL exhibited reduced negative surface charge, all SAA-dependent.

Conclusions:

• Orthopedic surgery-induced acute inflammation causes rapid, SAA-dependent HDL remodeling.
• Observed HDL changes (size, charge) may impair atheroprotective functions.
• SAA-driven HDL modifications provide a basis for qualitative HDL assessment in acute inflammatory states.