CIT ( Collagen Induced Therapy ) is a minimally invasive dermatological procedure in which fine needles are applied over the skin to puncture the stratum corneum. This therapy is used to induce collagen formation, neovascularization and growth factor production of treated areas. It has been used in a wide range of dermatologic conditions, including androgenetic alopecia (AGA) and alopecia areata.

Hair follicles (HF) are important not only in hair regeneration but also in wound healing and skin regeneration. The epidermal stem cells that reside in HF provide a substantial portion of wounded skin. Wound regeneration is delayed in the absence of HF. Wounds heal faster in skin with HF in the anagen phase than in the telogen phase. Conversely, Ito et al.reported that HF neogenesis occurs de novo via the Wnt signaling pathway following wounding in adult mice. A number of developmental pathways are recapitulated during both wound healing and HF cycling. Above findings suggest that the wound healing process could induce HF regeneration, which is defined as process of HF reentering anagen.

The dermal papilla (DP), a cluster of specialized fibroblasts, regulate the growth and activity of the various cells in the follicle, thereby, playing a key role in the regulation of hair cycling and growth. Hair follicle regeneration begins when signals from the mesenchyme derived DP cells reach multipotent epidermal stem cells in the bulge region.

Large numbers of molecular signals are involved in various phases of the normal hair cycle. The transition of telogen follicles into anagen is associated with activation of Wnt/beta-catenin/Lef1, Sonic Hedgehog (Shh), and STAT3 pathways and down-regulation of bone morphogenetic protein (BMP) signaling.

Microneedle stimulation itself could induce hair growth via Wnt/β-catenin signaling and VEGF. Activation of Wnt/β-catenin signaling is important not only for initiation and maintenance of hair morphogenesis but also for HF regeneration and growth of the hair shaft.

Expression of VEGF is induced after cutaneous injury, and it mediates angiogenesis and lymphangiogenesis during wound repair. VEGF is also a major mediator of hair growth and cycling via improving follicle vascularization. The increased VEGF in our results suggests that wound healing also occurs after microneedle stimulation.
A number of growth factors, prostaglandin, the sonic hedgehog, and Wnt/β-catenin signaling pathways are considered to be involved.

The clinical studies show great results with mean change in hair count at week 12 was significantly greater for the microneedling group 91.4 and improvement of the hair density of over 50%. In accordance to the clinical studies, we also use the adequate needle lenghts and CIT sessions protocol to achieve the best results for our patients.