Sudhakar and Sreekanth Ravi Stem Cell Biology Laboratory
The stem cell laboratory, set up with the generous support of two brothers - Sudhakar Ravi and Sreekanth Ravi of California, USA - is engaged in frontline research designed to apply knowledge of stem cell biology to the treatment of eye diseases. Stem cells, or undifferentiated cells from a donor eye, are cultured in a special medium to generate corneal cells that can then be transplanted into the eye of a person with corneal blindness. In the area of ocular surface damage, the laboratory has been particularly successful in developing a technique of culturing limbal stem cells ex-vivo on an amniotic membrane substrate and transplanting the resultant corneal epithelium into the patient's eye. The laboratory is also attempting to transdifferentiate stromal cells from the bone marrow into cells of neuronal lineage, which could then be taken further to grow retinal cells.
Sudhakar & Sreekanth Ravi Stem Cell Biology Laboratory and Champalimaud Translational Centre for Eye Research (C-TRACER)
Cultivation and characterization of human lacrimal gland cells for potential clinical application for post radiotherapy xerophthalmia
Investigators: Geeta K Vemuganti, Santosh G Honavar, Vijay Anand P Reddy1
Support: International Atomic Energy Agency, Austria
Dry eye condition due to failure or improper tear fluid secretion by lachrymal glands is a serious problem in patients undergoing radiation treatment for ocular tumors. With the aim of providing cell therapy for treating lacrimal gland dysfunction, our group has initiated work on culturing lacrimal gland cells using tissues that were harvested from patients undergoing exenteration. The preliminary results show that the lacrimal gland epithelial cells (LGEC) can be isolated from the source tissues by using a collagenase and hyaluronidase enzyme cocktail and can be cultured on denuded human amniotic membrane, matrigel and collagen. Further characterization of the cultured cells is in progress.
Evaluation and characterization of cancer stem cells in retinoblastoma tumor
Investigators: Geeta K Vemuganti, Santosh G Honavar, Chitra Kannabiran
Support: Indian Council of Medical Research, India
It is believed that a tumor tissue originates from a mutated stem cell and these stem-like cancer cells could influence disease prognosis and response to therapy. This study attempts to identify stem-like cells present in retinoblastoma tumors by characterizing different sub-populations of cells based on their light scatter properties and differential marker expression by FACS analysis. Our results indicate the presence of two different cell types in Rb tumors. The small cells designated as FSClow/SSClow were positive for CD44 and negative for CD133, CXCR4 and CD90 and the large cells designated as FSChigh/SSClow were positive for all the above markers. RT-PCR analysis revealed that the sorted FSClow/SSClow cells expressed high levels of retinal progenitor markers PROX1 and Syntaxin1A and therefore could represent the stem-like cells of Rb tumors.
An advanced surface for the cell therapy of limbal epithelium for ocular surface disease: Proof of concept and clinical trials
Investigators: Virender S Sangwan, Indumathi M
Support: Department of Biotechnology, India (Indo-Australian collaborative program)
This project aims to produce surface modified therapeutic contact lenses for in vitro culture and delivery of limbal epithelial cells for the treatment of ocular surface diseases. The project also includes a ‘proof of concept’ clinical trial in order to establish the safety and efficacy of this technique in comparison to the established technique of corneal epithelial transplantation using the human amniotic membrane (hAM) as a culture substrate. The plasma polymer coating technique allows exact control over the film thickness and with an appropriate chemistry; we anticipate that this technique would offer a better alternative to hAM for culturing limbal epithelial cells and their subsequent delivery on to the corneal surface.
Generation of disease specific inducted pluripotent stem cells from dermal fibroblasts of patients with retinal dystrophy
Investigators: Indumathi M, Chitra Kannabiran, Subhadra Jalali, Milind Naik
Support: Department of Biotechnology, India
Retinal dystrophy is a genetic disorder and also an age related disease resulting in gradual degeneration of the photoreceptors and the RPE cells. Therefore, cell replacement therapy offers a great promise in treating such diseases. However, an adult human retina does not harbour any stem cells to regenerate the lost cells. This has initiated a search for suitable cell sources that can give rise to the retinal cells. Recently, it was shown that adult somatic cells can be reprogrammed to ES-like cells by ectopic expression of some of the genes implicated in stemness and pluripotency. These cells were christened as induced pluripotent stem cells (iPSCs). Our group has initiated basic research towards exploring the feasibility of using iPS cells generated from adult dermal fibroblast as a stem cell source for deriving retinal cells.
A study of unilateral retinoblastoma with and without histopathologic high-risk features and the role of adjuvant chemotherapy – a groupwide phase 3 study
Investigators: Santosh G Honavar, Geeta K Vemuganti
Support: National Childhood Cancer Foundation, USA
The objectives of the study are:
a) To prospectively determine the prevalence of highrisk histopathologic features such as choroidal involvement, optic nerve invasion, scleral and anterior segment involvement in patients with unilateral retinoblastomas who had undergone enucleation;
b) To demonstrate that patients without certain high-risk features can be successfully treated with enucleation alone by estimating the event-free survival (EFS) and overall survival (S) where an event is defined as the occurrence of extraocular or metastatic disease;
c) To estimate the event-free survival (EFS) and overall survival (S) in patients with specific high-risk features who are uniformly treated with adjuvant chemotherapy where an event is defined as the occurrence of extraocular or metastatic disease; and
d) To estimate the incidence of toxicities associated with the proposed adjuvant chemotherapy.
Expected outcomes: The event-free survival and overall survival distributions will be estimated for patients with high risk features (treated with adjuvant chemotherapy) and separately for subjects without high risk features (treated with enucleation alone). Toxicities associated with the adjuvant therapy for patients with high risk features will be descriptively summarized. The study is still in the active recruitment phase.
Indian Council of Medical Research National Retinoblastoma Registry
Investigators: Santosh G Honavar, P M Fairooz
Support: Indian Council of Medical Research, India
The objectives of the proposal are to develop a reliable database on retinoblastoma, record the magnitude of the problem, assess the efficacy of the treatment protocol and remission status and study the mortality rate.
The project is being done in a prospective fashion. All new patients diagnosed with retinoblastoma from April 1, 2009, are being registered. Details of the patients are recorded manually by a research fellow in the proforma designed by ICMR. Then a data entry operator enters the data in a web page. The data is updated and edited periodically.
Applied value of the project: The project will enable researchers and clinicians to understand retinoblastoma and its clinical presentation in the Indian scenario, which is different from that in western literature. The data collected at the end of one year across the country will open up new avenues for research, while increasing awareness about any shortcomings in the diagnosis and management of retinoblastoma, thus helping in salvaging more eyes.