e responsible for 是指对某事负责
而be held(hold的过去分词,表被动) responsible for 则是指
someone else will come to you if things don't turn out right.
也就是someone will hold you responsible for something.有人会拿你试问
We will be held responsible for their safety .
相当于We will be considered responsible for their safety.
If something go wrong with their safety,we are to blame.
其实翻译成中文基本上就是我们对他们的安全负责,(如果出了问题,我们承担责任）.
而你给出的例句"Oxidized cholesterol may be responsible for furring up the arteries."
这句就显然不能用到be held responsible for,因为没有人会去找”Oxidized cholesterol”算账.