# Chicken Feather Keratin Peptides for the Control of Keratinocyte Migration
## 3 Results and Discussion  
### Cell Metabolic Activity and Migration  
Cellular migration is of the utmost importance for several mechanisms, such as immune response, wound repair and tissue homeostasis [21]. On the other hand, an aberrant cell migration leads to several pathologies such as the invasion of malignant cells into the surrounding tissue, with the formation of tumour metastasis, leading to a poorer prognostic for the patient [22]. A patient with a chronic wound has a compromised quality of life due to excruciating pain and the constant need for medical care, resulting in a significant burden to the health system worldwide. Briefly, the physiological process of wound healing has several steps, such as haemostasis, inflammation, proliferation, and remodelling. The haemostasis starts as soon as the injury occurs and is characterized by vasoconstriction and blood clotting. This stage is of the utmost importance as it prevents excessive blood loss and provides the required matrix for cell migration. Upon the inflammation stage in which phagocytic cells are recruited, the proliferation stage starts. At this stage, several growth factors and cytokines are recruited by different cell types, such as keratinocytes. The final stage is characterized by the formation and organization of collagen bundles [21]. If an arrest or delay occurs in any of these stages, particularly in the inflammation stage, it can lead to the formation of a chronic wound. It is known that keratinocytes have an important role in wound healing, particularly in re-epithelial [23]. The non-migration of these cells to the injury site is associated with the clinical phenotype of chronic wounds. Even though keratinocytes are not motile in normal steady-state condition, in the presence of signalling molecules, they can migrate to re-epithesize the wound site [24]. Consequently, the enhancement of the keratinocyte migration rate is of the utmost importance for wound re-epithelization, particularly in the case of chronic wounds [25]. On the other hand, cancer metastization or invasion into the surrounding tissue leads to a poorer prognostic for the patient, as in the case of invasive squamous cell carcinoma [22]. Squamous cell carcinoma and basal cell carcinoma are keratinocyte carcinomas, particularly diagnosed in fair-skinned populations [26; 27]. The decrease in cell migration might result in a less invasive tumour. The ability of keratinocytes to migrate from one edge of the scratch, performed on a cell confluent monolayer, to its opposite edge was evaluated for a period of 24 h, in the presence and absence of the peptides designated by P188D. First, a preliminary cell viability study using fibroblasts demonstrated that the presence of 25 and 50 ug/mL of peptides resulted in 94.2 \(\pm\) 0.77 and 92.4 \(\pm\) 1.55% of viable cells, respectively. Therefore, 45 ug/mL was the chosen concentration for the following tests. The effect of P188D peptide on keratinocyte migration was evaluated up to 24 h hours of contact. The presence of the peptide seems to decrease the keratinocyte migration rate in comparison to the control, this effect being clear at 24 h of contact (Figure 1). Thus, it seems that the presence of the peptides negatively affects keratinocyte migration, which could be important to reduce the invasiveness of skin cancer cells. The microbial degradation of a protein results in several peptides with different sizes, amino acid composition and sequence. It is known that these characteristics have a striking effect on several physiologic mechanisms [28]. Therefore, to better understand the effect observed on keratinocyte migration, peptides were fractioned into smaller fractions using different percentages of acetonitrile 20%, 40% and 80% (20%, 40% and 80% fraction peptide). The final result was a solution with a narrowed peptides distribution. The influence of these fractions on the keratinocyte metabolic activity and migration was once again evaluated.