Pattern of expression of CCN family members Cyr61, CTGF and NOV in human acute and chronic wounds

The CCN family is a group of extremely cysteine-rich proteins that are found within the extracellular matrik and are comprised of cysteine-rich 61 (Cyr61/CCN1), connective tissue growth factor (CTGF/CCN2) and nephroblastoma over-expressed (NOV/CCN3). Collectively, these proteins stimulate mitosis, adhesion, apoptosis, extracellular matrix production, growth arrest and migration, and regulate angiogenesis, tumour growth, placentation, implantation, embryogenesis and endochondral ossification. Despite such diverse activity, CCN protein function has not been explored in human wounds and healing. In the present study, we investigated the expression of these proteins in samples of normal, acute and chronic wounds using immunohistochemical staining and real-time quantitative RT-PCR. Statistical analysis was performed using the Fisher's exact test. Our results showed that, although all CCN proteins were present in normal, acute and chronic wounds, their expression levels differed, particularly in the case of connective tissue growth factor (CTGF), for which significantly reduced levels were found in chronic wounds compared to acute wounds (p<0.002). Thus, the lack of CTGF in wound tissues may contribute to the abnormal healing of clinical wounds. This suggests that CCN proteins may play an important role in human tissue wound healing. This further suggests that human wound healing may be promoted by manipulating the levels of this protein.