Digital Public Defence: Ayyad Khan

MD Ayyad Ahmad Zartasht Khan at Institute of Clinical Medicine will be defending the thesis Culture and Storage of Retinal Pigment Epithelial Cells for Regenerative Medicine Purposes and the Use of Sericin to Improve Graft Quality for the degree of PhD (Philosophiae Doctor).

The public defence will be held as a video conference over Zoom.

The defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.

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Due to copyright reasons, an electronic copy of the thesis must be ordered from the faculty. In order for the faculty to have time to process the order, it must be received by the faculty no later than 2 days prior to the public defence. Orders received later than 2 days before the defence will not be processed. Inquiries regarding the thesis after the public defence must be addressed to the candidate.

Digital Trial Lecture – time and place

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Adjudication committee

  • First opponent: Assistant Professor Fredrik Lanner, Karolinska Institutet
  • Second opponent: Professor Anu Kauppinen, University of Eastern Finland
  • Third member and chair of the evaluation committee: Professor emeritus Trond Buanes, University of Oslo

Chair of the Defence

Professor emeritus Haakon Breien Benestad, University of Oslo

Principal Supervisor

PhD Jon Roger Eidet, Oslo University Hospital


Transplantation of retinal pigment epithelial cells (RPE) is gaining popularity as a potential treatment modality for sight-threatening diseases. The aim of this thesis was to (1) develop a system to assess the quality of cultured epithelia prior to transplantation, (2) find a suitable storage temperature and storage medium for the short-term hypothermic storage of mature RPE cell sheets, and (3) explore whether RPE quality (viability, maturation, and morphology) could be improved using the silk protein sericin as a culture medium additive. 

Experiments were conducted on cultured primary human RPE, adult retinal pigment epithelial cell line-19 (ARPE-19), induced pluripotent stem cell-derived RPE (iPSC-RPE), human conjunctival epithelial cells, and human epidermal keratinocytes.

The thesis (1) presents a computerized method to quantify immunofluorescence and cell morphometry in cultured epithelia, (2) suggests that temperatures between 4°C and 16°C are suitable for short-term hypothermic storage of mature RPE cell sheets, (3) describes a serum-free storage medium for short-term storage of differentiated RPE, and (4) shows that supplementing the culture medium with 10 mg/mL sericin improves RPE viability, maturation, and morphology in vitro.

Finally, a hypothesis is presented suggesting that sericin-induced melanogenesis in RPE is associated with elevated levels of superoxide dismutase, hydrogen peroxide, and inflammatory proteins. In addition to the field of retinal regenerative medicine, the results discussed herein carry potential implications for our understanding of retinal physiology, epithelial physiology, and melanogenesis.

Additional information

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Published Feb. 25, 2021 10:44 AM - Last modified Mar. 15, 2021 11:01 AM