Can Izanagi help to escape natural death? As far as I understand Izanami determines the fate and Izanagi helps to escape the fate in cost of a Sharingan. Death is the ultimate fate of all of us. So can Izanagi be used to cheat natural death. Then a Rinnegan and Sharingan wielder can be virtually immortal!
Can Izanagi cheat natural death.
PARTLY SPOILER 
Yes, you can use the Izangi to revive yourself after death. I don't know how, but Madara had implanted the Izangi in his eye before his death and used it to come back to life, for exchange for his right eye.