A 58-year-old man with a 10-year history of osteoarthritis of the knees presents to the outpatient clinic. He has been taking ibuprofen 400 mg three times daily for the past 6 months for pain relief. On examination, his blood pressure is 148/92 mmHg (previously 130/80 mmHg 6 months ago). Serum creatinine has risen from 0.9 mg/dL to 1.4 mg/dL. Urinalysis shows mild proteinuria (1+). He denies any history of diabetes or primary renal disease. Which of the following mechanisms best explains the renal dysfunction observed in this patient?