Masafumi Myoishi

BACKGROUND: The endoplasmic reticulum (ER) responds to various stresses by upregulation of ER chaperones, but prolonged ER stress eventually causes apoptosis. Although apoptosis is considered to be essential for the progression and rupture of atherosclerotic plaques, the influence of ER stress and apoptosis on rupture of unstable coronary plaques remains unclear. METHODS AND RESULTS: Coronary artery segments were obtained at autopsy from 71 patients, and atherectomy specimens were obtained from 40 patients. Smooth muscle cells and macrophages in the fibrous caps of thin-cap atheroma and ruptured plaques, but not in the fibrous caps of thick-cap atheroma and fibrous plaques, showed a marked increase of ER chaperone expression and apoptotic cells. ER chaperones also showed higher expression in atherectomy specimens from patients with unstable angina pectoris than in specimens from those with stable angina. Expression of 7-ketocholesterol was increased in the fibrous caps of thin-cap atheroma compared with thick-cap atheroma. Treatment of cultured coronary artery smooth muscle cells or THP-1 cells with 7-ketocholesterol induced upregulation of ER chaperones and apoptosis, whereas these changes were prevented by antioxidants. We also investigated possible signaling pathways for ER-initiated apoptosis and found that the CHOP (a transcription factor induced by ER stress)-dependent pathway was activated in unstable plaques. In addition, knockdown of CHOP expression by small interfering RNA decreased ER stress-dependent death of cultured coronary artery smooth muscle cells and THP-1 cells. CONCLUSIONS: Increased ER stress occurs in unstable plaques. Our findings suggest that ER stress-induced apoptosis of smooth muscle cells and macrophages may contribute to plaque vulnerability.

AIMS: Finerenone (BAY 94-8862) is a novel non-steroidal mineralocorticoid receptor antagonist. The aim of this study was to compare the efficacy and safety of seven once-daily oral doses of finerenone (1.25-20mg) and placebo in 96 patients with type 2 diabetes mellitus (T2DM) and diabetic nephropathy (DN) receiving a RAS blocker. METHODS: ARTS-DN Japan was a multicenter, randomized, double-blind, placebo-controlled, phase 2b study. RESULTS: Analysis of the urinary albumin-to-creatinine ratio (UACR) at day 90 relative to baseline indicated a nominally significant effect of finerenone. The UACR at day 90 relative to baseline for each finerenone treatment group was numerically reduced compared with placebo. No serious adverse events (AEs) or deaths were reported and no patients experienced treatment-emergent AEs resulting in discontinuation of study drug. Small mean increases in serum potassium level were observed in the finerenone treatment groups (0.025-0.167mmol/L) compared with the placebo group (-0.075mmol/L); no patients developed hyperkalemia. CONCLUSION: When given in addition to a RAS inhibitor, finerenone reduced albuminuria without adverse effects on serum potassium levels or renal function in Japanese patients with T2DM and DN.