Healthcare and Medicine Reference
In-Depth Information
While published reports using systemic cyclosporine A in allogeneic
CLET span only 6 months (Daya et al. 2005, Shortt et al. 2008), longer term
systemic immunosuppression is recommended for KLAL and high risk
PK patients when using tacrolimus—until at least 18 months from the last
rejection episode (Miri et al. 2010), or mycophenolate mofetil—for up to 2
years in penetrating limbo-keratoplasty for total bilateral LSCD (Reinhard
et al. 2004). Using combined therapy with mycophenolate mofetil and
tacrolimus, KLAL rejection rate was 17%, which is signifi cantly lower than
in other series (Liang et al. 2009).
Cultivated Oral Mucosa Transplantation (COMET)
The results of COMET for bilateral total LSCD have been reported in 59
patients since 2004. At year 3rd, visual acuity (VA) had improved in 95% of
19 eyes followed for a mean of 55 months (Nakamura et al. 2011). However,
the mean best-corrected VA was of about 20/40 only. While 74% of these
cases received also amniotic membrane transplantation, 37% developed
PED postoperatively; 71% of them suffered from SJS and 90% had also
received mitomycin C as adjunctive therapy to prevent scarring after fornix
reconstruction, performed simultaneously to COMET. Ocular hypertension
was observed in 3 eyes (16%).
In another series of 40 patients with a mean follow-up of 25.4 months
(Satake et al. 2011) COMET was followed by “immediate” epithelialization
in all patients. However, the ocular surface stability declined during the fi rst
6 months leading to PED. At year 2nd and 3rd, the acquisition of a stable
ocular surface was 59.0% and 53.1%, respectively. The different phenotype
of oral mucosa compared to corneal epithelium would explain this tendency
to PED, and all patients had peripheral corneal vascularization and stromal
opacity that affected the fi nal visual acuity.
To improve the results of CLET and COMET we need to progress in
several aspects, as determining the actual number of stem cells present
in CLET and COMET cell sheets, a better knowledge of the behavior of
transplanted cells and the role of the adequate limbal “niche” in the survival
of these. Beyond the provision of new limbal cells, future advances may
require the reconstruction of these “niches” and possibly the replacement
of other components of the ocular surface necessary for maintaining its
physiology (Baradaran-Rafi i et al. 2010).
Autologous Biological-haptic Keratoprostheses (OOKP, T-OKP)
Of the several types of artifi cial cornea that have been used in cases with
severe LSCD, the longest record corresponds to OOKP. The group of
Falcinelli reported 85% (of 181 cases) anatomical survival after 18 years, and
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