A 24-year-old African American man with sickle cell disease is brought to the emergency department because of a 3-hour history of severe right upper quadrant pain radiating to his right shoulder. He has had two similar episodes over the past 18 months. He denies fever, chills, jaundice, or pale stools. Temperature is 37.1°C (98.8°F). Examination shows right upper quadrant tenderness without peritoneal signs; Murphy's sign is absent. Laboratory studies show:
Hemoglobin: 8.2 g/dL
Reticulocyte count: 11%
Total bilirubin: 3.8 mg/dL
Direct (conjugated): 0.4 mg/dL
Indirect (unconjugated): 3.4 mg/dL
A plain abdominal X-ray shows multiple radio-opaque densities projected over the right upper quadrant. Ultrasound confirms multiple stones confined to the gallbladder; the common bile duct and intrahepatic ducts are stone-free.
Which of the following most likely accounts for the development of gallstones in this patient?