Background
Noncultured extracted hair follicle outer root sheath cell suspension (NC‐EHF‐ORS‐CS) is an upcoming surgical technique to treat stable vitiligo. Conventionally it employs trypsin to tap the hair follicle (HF) reservoir for autologous melanocytes and their precursors for transplantation. However, a perifollicular dermal sheath composed of type 1 collagen encases the target ‘bulge’ region of the HF. Adding collagenase type 1 would digest the ORS, facilitating better release of cells.
Aim
To compare the repigmentation achieved using trypsin and a combination of collagenase plus trypsin, respectively, with dermabrasion alone, and to compare cell counts, viability and composition of both suspensions.
Methods
This was a randomized, double‐blind, comparative, therapeutic trial, conducted as a pilot study on 22 patients with stable vitiligo. Three similar patches were randomized into three parallel treatment arms [(A) trypsin plus collagenase, (B) trypsin alone and (C) dermabrasion with vehicle alone]. Each patient’s HF sample was divided and digested by the two methods, and transplanted as suspensions onto dermabraded patches, while a third dermabraded patch received the vehicle only. Suspensions were sent for laboratory analysis. Repigmentation was assessed over a follow‐up of 6 months.
Results
There was a significant increase in cell yield and comparable viability when collagenase was added. Immunohistochemical and flow cytometry studies showed a nonsignificant increase in HMB45+ melanocytes and their precursor stem cells in group A. This trend was reflected clinically in the extent of repigmentation [group A (33.22%) > B (24.31%) > C (16.59%); P = 0.13]. Adding collagenase induced significantly higher repigmentation than dermabrasion alone (P < 0.05).
Conclusions
Incorporating collagenase type I into the conventional NC‐EHF‐ORS‐CS technique resulted in enhanced retrieval of pigment‐forming cells and subsequently improved repigmentation in vitiligo.