Research and Development: Healing Refractory Wounds by Macrophages

Macrophages constitute a major, widely dispersed cell population responsible, among other functions, for the wound healing process. They eliminate pathogens and dead cells by phagocytosis, but also produce and secrete various growth factors and cytokines (hormone-like substances) involved in wound healing.

Abnormal wound healing can be found in elderly patients, and in those who suffer from many chronic diseases (such as Diabetes Mellitus, Obesity and other medical conditions), which may cause prolonged morbidity and even mortality.

The mechanism determining the entry of white blood cells from the blood circulation into tissues, their activation, migration to and differentiation within tissues has not been fully clarified. In order to overcome this problem, the research team at MDA blood services has developed an innovative approach for treating chronic, severe wounds by applying a suspension of activated macrophages (a subset of white blood cells present in the blood) directly into the wounds.

The macrophage suspension is prepared from a "regular" blood unit, donated by healthy volunteers. The cells are separated in a closed sterile system, and used, as a "topical" application, for the treatment of severe wounds, such as pressure ulcers, chronic wounds occurring after Coronary Bypass Surgery (infected wounds in the sternum or following the saphenous vein harvesting in the patients legs), general surgical wounds and others. In many studies this method proved to be more effective than other conventional methods used to treat refractory and infected wounds.

The production and application of the macrophage suspension has been approved by the Israeli Ministry of Health in 1995, and has been used since in different clinical settings. Hundreds of patients were treated so far. The proportion of healed closed ulcers by macrophages application was more than three folds greater than all the conventional methods used. In most patients, a full recovery was achieved following 1-2 applications. No side effects were observed, and no patient died as a result of the treatment. The annual operating costs of the R&D unit are 200,000 US$

As Macrophages are involved in many other processes in the human body new applications should be pursued, to maximize the potential and outmost clinical importance of these cells.