Quantification and Stratification: Wound Research in the Future

In vivo monitoring the changes of interstitial pH and FAD/NADH ratio by fluorescence spectroscopy in healing skin wounds

The aim of our study was to evaluate the changes of interstitial pH and flavin adenine dinucleotide (FAD)/reduced nicotinamide adenine dinucleotide (NADH) ratio in healing skin wounds using fluorescence spectroscopy in Sprague Dawley rats. In the experiment, excisional and incisional models of wound healing were used. The florescein as the pH-sensitive probe using excitation spectra (lambda(Em) = 535 nm) was used for the measurement of pH changes, and synchronous fluorescence spectra (Deltalambda = 60 nm) for the monitoring of FAD/NADH ratio changes were measured from the surfaces of healing wounds. Increase of interstitial pH and FAD/NADH ratio was recorded during the time interval from the 15th to the 65th minute after surgery. The decrease of pH between the 48th and the 72nd hour after surgery as well as the increase of FAD/NADH ratio between the 72nd and the 96th hour of wound healing were recorded. The results indicate that the use of fluorescence spectroscopy may be considered as a valuable tool for noninvasive in vivo monitoring of selected redox parameters in the early phases of wound healing.

Significance of cell cycle for wound stratification in clinical trials: analysis of a pressure ulcer clinical trial utilizing cyclin D/cdk4

During the past 5 years, progress in the treatment of pressure ulcers appears to have reached a plateau. Several factors in the design of recent clinical studies may have contributed to this situation. These factors include the criteria chosen for patient selection, small sample size, and lack of a concisely defined final clinical outcome. Hunt noted that wound stratification according to a patient's physiological characteristics may be a key to quantifying differences among clinical treatments. To address this issue, we examined the expression of cyclin D/cdk4 in pressure ulcer fibroblasts taken from tissues during a recent clinical trial. The treatment groups included patients treated with the following regimens: placebo, granulocyte macrophage-colony stimulating factor alone, basic fibroblast growth factor alone, or granulocyte macrophage-colony stimulating factor and basic fibroblast growth factor given in sequence. Immunocytochemical colocalization of cyclin D and cdk4 showed that, before the initial treatment began, patients were distributed disproportionately among treatment subgroups in regards to the initial expression of these markers. For example, we found that compared with other subgroups, ulcer fibroblasts in the basic fibroblast growth factor treatment group showed a much lower expression of cyclin D/cdk4 at day 0. However, this group exhibited higher levels of expression of this complex after 35 days of treatment. This study shows that measurement of cyclin D/cdk4 expression permits more accurate stratification of patients within treatment subgroups, measurement of a cell's ability to detect the presence of functional cytokines, identification of area(s) of failure within the G1 of the cell cycle, and a basis for critical evaluation of various treatments.