Effect of human cord blood-derived stem cells on induced diabetic retinopathy in adult albino rat: histological and immunohistochemical study

Diabetic retinopathy is a leading cause of blindness in adults. Recent developments in stem cell field have widened the prospects of applying cell-based therapies to regenerate ocular tissues. This study was done to explore the potential effect of human cord blood-derived stem cells on induced diabetic retinopathy in adult albino rats. This study was performed on 26 adult male albino rats. Animals were randomly divided into four groups. Group I [control group]: five control animals each received single intraperitoneal injection of citrate buffer. Group II: seven animals in whom diabetes was induced by single intraperitoneal injection of streptolotocin and animals were killed 4 weeks later. Group III: seven animals in whom diabetes was induced the same way as in group II and animals were killed 8 weeks later. Group IV: seven animals with diabetes were injected with ferrous oxide-labeled cord blood-derived stem cells 4 weeks after induction of diabetes and were killed 4 weeks after stem cell injection, All sections from retina of all groups were subjected to Haematoxylin and eosin, Prussian blue staining and CD34 immunohistochemistry. Statistical analysis was done to measure the mean number of ganglion cell nuclei and the wide clear areas around them. Groups II and III showed progressive histological changes of diabetic retinopathy. Group IV exhibited a significant increase in the number of ganglion cells with less clear areas compared with group III. Moreover, cells positive for Prussian blue and CD34 were detected in different retinal layers of group IV. Human cord blood-derived stem cells injected into rats with diabetic retinopathy contributed to restoration of ganglion cell layer and vascular repair, which may postulate a potential therapeutic intervention for diabetic retinopathy

Correction of Aberrant pre mRNA splicing using antisense oligonucleotides in B thalassemia patients with known IVS-I,nt 110 mutation

1VS In l 110 mutation is the most common mutation in Egyptian thalassemics. The mutation causes aberrant splicing ofpre-mRNA resulting in labile RNA causing deficient B-globin chain synthesis. Antisense oligonucleotide strategy is one of the more simple technique in gene therapy. Using oligonucleotides covering the aberrant splice site gives chance for normal splicing and correction of the anomaly at the RNA level. Blocking of aberrant splicing at IVS 1nt 110 site of B-globin pre-mRNA using antisense oligonucleotides results in subsequent restoration of normal mRNA production in B-thalasseamia patients with IVS 1nt 110 mutation This study involved 10 patients with known IVS IntllO mutation; 6 homozygous and 4 heterozygous patients peripheral blood mononuclear cells were separated and duplicate liquid culture systems were set using erythropoietin and stem cell factor with and without antisense oligonucleotides [20 micro. mol/ml]. Correction of aberrant splicing was evaluated by estimation of total hemoglobin, hemoglobin F, and a reverse transcriptase polymerase chain reaction followed by agar gel electrophoresis was used to amplify and detect both aberrant mRNA and normal mRNA in duplicate samples. Five cases [50%] showed correction after antisense oligonucleotide treatment, two cases showed the appearance of normal mRNA band with absence of aberrant band and in 3 cases an increased ratio of normal mRNA band to aberrant band was found [from 2:1 to 3:1 in two cases and from 2:1 to 4:1 in the third case]. The 5 corrected cases showed significant increase in total Hb which varied between 4 to 6 folds increase. Antisense oligonucleotide treatment corrects splicing ofpre-mRNA leading to appropriate expression of B-globin mRNA which may pave the way for treatment of thalassaemia.