(HealthDay News) -- Gangrene occurs when a portion of bodily tissue dies due to lack of blood supply to the area.

The U.S. National Library of Medicine says these factors increase a person's risk of developing gangrene:

• Suffering a serious injury.
• Having a disease of the blood vessels, such as hardening of the arteries.
• Being diabetic.
• Having a compromised immune system (ie., from HIV or chemotherapy).
• Having surgery.