Background: Viability and survival of stored micrografts during hair follicle transplantation are important limitations of micrograft transplantation procedures. In this study, we investigated the effect of different storage solutions and inhibitors of apoptotic cell death (ACD) on hair follicle cell viability by measuring in vitro hair shaft elongation (HSE) for 5 days.
Methods: Micrografts from informed patients undergoing routine micrograft transplantation were stored for 5 hours at room temperature in phosphate-buffered salt solution (PBS) or HEPES-buffered Dulbecco's modified Eagle's medium (DMEM), containing different concentrations of the ACD-inhibitors aminoguanidine (AMG), hormones (insulin, hydrocortisone), 14,15-epoxy-eicosatrienoic acid (14,15-EET), or combinations of these.
Results: In vitro, HSE was significantly increased in micrografts stored in DMEM compared with PBS (2.3%+/-0.6% vs. 28.4%+/-3.9%, P<0.0001). DMEM supplemented with AMG (10 microg/mL) or 14,15-EET (1 ng/mL) further increased in vitro HSE (33.9%+/-7.1%, p=0.01, and 32.8%+/-6.1%, P=0.02, respectively). Evaluation of ACD in stored micrografts, performed by determination of cytoplasmic histone-associated DNA fragments, confirmed the results found by HSE. ACD was detectable after a 36-hour culture in serum-containing medium and was higher in micrografts stored in PBS compared with micrografts stored in DMEM (A405nm/A492nm: 1.63+/-0.21 vs. 1.42+/-0.07, respectively; P<0.01). The addition of AMG further decreased serum-induced ACD in the micrografts (DMEM 1.42+/-0.07 vs. DMEM/AMG 0.90+/-0.11, P<0.0001).
Conclusion: Our study demonstrated an important role of ACD in micrograft transplantation surgery. Preconditioning of micrografts with storage buffers containing inhibitors of ACD could prevent serum-induced ACD after transplantation and might increase the viability of micrografts and the clinical outcome in micrograft transplantation.