Chronic Morphine Use Delays Wound Healing

They report their data in the February 2010 issue of The American Journal of Pathology.

Morphine acts on cells in the central nervous system, resulting in pain relief and analgesia; however, morphine use may also affect the immune system. Indeed, chronic morphine users and opioid abusers have inadequate wound closure and increased susceptibility to infection.

To further address this issue, Martin et al examined wound healing in a mouse model of chronic morphine use/abuse. In the presence of inflammation, chronic morphine exposure resulted in a marked decrease in wound closure, compromised wound integrity, and increased bacterial sepsis. With morphine exposure, expression of particular immune molecules was altered, which led to decreased recruitment of immune cells to the wound site. New blood vessel formation and recruitment of replacement cells were also suppressed in these animals. These data suggest that the immunosuppression due to morphine treatment delays immune cell recruitment, leading to lack of bacterial clearance and delayed wound closure.

Dr. Roy's group concludes that "these studies provide an in vivo tool by which further mechanistic experiments can be performed to address why, clinically, heroin-addicted patients often present with infected non-healing wounds. Understanding these underlying mechanisms affords improved treatment options not only for chronic morphine users and abusers, but can also have translational implications for immuno-compromised populations such as the elderly or those who are chronically stressed."