Related to security is isolation.

这也是一种完全倒装句：过去分词（短语） +  be  +  主语

正常语序是：Isolation is related to security.  隔离（的目的）是与安全有关。

又如：

Added to the shyness of his look was a faint streak of melancholy.

Seated beside the teacher were some small children.

Cut in the ring was a name:  Agnes.

Scattered on the floor were several books and magazines.

Ranked second and third were grocery and electronics customers.