Glenn O'Brien, the editorial director who last year took over Interview magazine and Brant Publications' other titles, Art in America, The Magazine Antiques, and the new design title Modern, has left the company, a publicist confirmed to New York. It's the latest in a long string of leadership changes, ever since longtime editor Ingrid Sischy left and her partner, publisher Sandra Brant, sold her half of the company in January of 2008.