Hematopoietic Stem Cell Therapy in Chronic Wounds Using a Pressure Sore Model

In January of 2007, the University Hospital in Basel, Switzerland started a pilot study, which concluded in December of the same year. The study evaluated the ease of use, safety, and potential effects of the use of hematopoietic stem cells in chronic wounds like pressure sores.

Participating Patients

The case study recruited 35 patients. The patients were adults in the age range of 18 to 50. They recruited both sexes for the experiment and no healthy volunteers were accepted. The inclusion criteria for the volunteers included:

• The patients were either paraplegic or tetraplegic.
• The patients suffered with pressure sores on the sacrum.
• The volunteers possessed sacral pressure sores classified between Grade III and IV, according to the classification of Daniel and Seiler.
• The test subjects provided written consent for the experiments.

The Exclusion Criteria for the Volunteers Included:

• The patients consumed steroids and other immunosuppressive drugs.
• The patients possessed autoimmune or rheumatoid diseases.
• The volunteers had HIV.
• The patients had Hepatitis B or C.
• The test subjects were smokers.
• The volunteers had diabetes mellitus.
• The volunteers had coronary artery disease.
• The test subjects had peripheral vascular disease.

Nearly two-thirds of the patients fell under the exclusion criteria due to several factors such as age, lack of written consent, and preexisting conditions, so only three patients were left who actually participated in the study.

Facility and Research Staff

The clinical study took place at the Swiss Paraplegic Center, in Nottwill, Switzerland. The center also handled the recruitment for the experiment, and its own Dr. Mirjam Zweifel-Schlatter acted as the sub-investigator. The University Hospital in Basel was the collaborator and sponsor of the project. Dr. Oliver Scheufler of the University Hospital directed the study.

The Process

The study aimed to specifically observe possible accelerated healing of uncomplicated wounds and the enhanced healing of complicated wounds. The test subjects took part in a process consisting of five parts.

1. First, a surgical process was used that involved the partial debridement, or removal, of the pressure sore. Doctors removed the wound using cauterization and applied warm compresses. Wound dressings included gauzes treated with Ringer’s lactate. They did not use any disinfectant in the process.
2. Next, doctors retrieved hematopoietic stem cells from the patients’ bone marrow. Specifically, they harvested around 100 mL of bone marrow from the posterior iliac crest through repetitive aspirations and punctures. The goal for extraction was one million CD 34+ cells per patient. They kept the stem cells under storage at the University Hospital and under GMP conditions.
3. After two days, the patients received injections of stem cells in suspension. Each wound received 50,000 CD 34+ cells in 100-microliter saline per cm2 of wound surface in one half of the surface. The injection to the other half of the wound surface was a cell-free saline to act as control. The test took biopsies on days 0, 3, 5, 12, and 19 after the stem cell therapy. Scientists performed and studied the biopsies at the University Hospital’s Institute of Pathology.
4. After a period of three to four weeks, a second surgical procedure took place. Doctors completely extricated the rest of the wound from the surface. They finished by closing the defect with a fasciocutaneous flap.
5. Following the removal of the treated wound, professionals clinically studied the morphometry of the wound in three-dimensional analysis with the aid of laser scanning. They later reconstructed the wound with the help of a local flap three weeks after the second surgery.

Results of the Study

The experiment ended prematurely because, out of 35 recruited patients, most could not participate because of either ambiguous consent, lack of age, ulcers higher than grade IV, or other preexisting conditions that interfered with the experiment. Doctors only examined three total patients. After the initial filing with the United States Library of Medicine on September 26, 2010, no one ever updated the study.

They eventually published the study on January 23, 2014. Out of the 120 biopsies examined, none of them showed any significant change in the wound model. The CD 34+ cells eventually disappeared after the third day of testing. Healing after the surgery in the patients was uneventful.

Conclusion

The researchers concluded that the safe use of hematopoietic cells, as well as the ideal source and cell type, was inconclusive, due to the lack of a suitable model to examine the effect of cell therapies on chronic wounds. However, since the analysis of the wound volume and histology occurred without additional morbidity, the researchers believe this model is ideal for the future study of wound healing.

Sources

• Hematopoietic Stem Cell Therapy in Chronic Wounds Using a Pressure Sore Model
• Progenitor cell therapy for sacral pressure sore