Maha Shahin

Mesenchymal stem cell-based therapy for the treatment of type 1 diabetes mellitus.

The pathophysiology of Type 1 diabetes (T1D) appears largely related to an innate defect in the immune system culminating in a loss of self tolerance and destruction of the insulin producing β-cells. Currently, there is no definitive cure for diabetes. Insulin injection does not mimic the precise regulation of β-cells on glucose homeostasis, leading long term to the development of complications. Other therapeutic approaches therefore, are necessary and cell therapy is thought to be a possible approach. In this sense, mesenchymal stem cells (MSCs) can offer a promising possibility that deserves to be explored. MSCs are multipotent non-hematopoietic progenitor cells. Their therapeutic potentials have recently been brought into the spotlights of many fields of research. Although the regenerative capabilities of MSCs have been a driving force to initiate studies testing their therapeutic effectiveness, their immunomodulatory properties have been equally exciting. MSCs possess specific immunomodulatory properties that would appear capable of disabling immune dysregulation that leads to β-cell destruction in T1D. Furthermore, MSCs can be sequentially cultured in specially defined conditions and their differentiation extends toward the β-cell phenotype and the formation of insulin producing cells (IPCs). To date, the role of MSCs in T1D remains completely unexplored. We herein summarize multiple strategies that have been proposed and tested for its potential therapeutic benefit for T1D.

MRI in Diagnosis of Orbital Masses

Purpose: To evaluate the role of diffusion-weighted magnetic resonance imaging and proton magnetic resonance spectroscopy in diagnosis of different orbital masses and their advantages over conventional magnetic resonance imaging. Methods: The study included 32 patients presenting with proptosis. Every patient was subjected to a clinical examination; conventional MRI “T1 weighted, T2 weighted, and post-contrast T1 weighted if needed;” diffusion-weighted MRI; and proton magnetic resonance spectroscopy. Orbitotomy was performed, the orbital mass was excised, and histopathological examination was performed. Results: Diffusion-weighted MRI can be used to differentiate between benign lesions and malignant tumors in 75% of cases; however, overlap occurred in 25% of cases with benign tumors showing restricted diffusion while proton magnetic resonance spectroscopy could differentiate between benign and malignant tumors in 93.7% of cases. Conclusion: Diffusion-weighted MRI and proton magnetic resonance spectroscopy increased the accuracy of diagnosis of orbital masses through giving in vivo tissue characterization; with magnetic resonance spectroscopy being more accurate.

Insight into 144 patients with ocular vascular events during VEGF antagonist injections

Aim To record ocular vascular events following injections of vascular endothelium growth factor (VEGF) antagonists. Methods Collaborative multicenter case series (48 cases), literature reviews (32 cases), and reports to the FDA (64 cases) of patients that had vascular occlusions during anti-VEGF therapy were collected and analyzed. Results A total of 144 cases of ocular vascular events were identified, with these diagnosed a median of 15 days after anti-VEGF injection. The majority of patients had pre-existing risk factors for cardiovascular events and nine patients had a prior history of glaucoma. Mean visual acuity dropped by 6.4 lines with severe visual loss after injection to NLP (five eyes), LP (six eyes), and HM (two eyes). The overall risk of ocular vascular events following a VEGF antagonist injection was 0.108% in the general population and 2.61% in the diabetic population. Mean retinal arterial constriction after intravitreal bevacizumab in 13 eyes was 21% (standard deviation = 27%), and mean retinal venous constriction was 8% (standard deviation = 30%). Conclusion Ocular vascular events are rare during anti-VEGF therapy, but can lead to severe visual loss and may be caused by a number of factors including the vasoconstrictor effect of the drug, a post-injection rise of intraocular pressure, patient stress as a result of the procedure, and the patient’s natural history of underlying ocular or systemic diseases. The diabetic population appears to have a tendency towards ocular vascular occlusions.

Ocular manifestations of idiopathic aplastic anemia: Retrospective study and literature review

Aplastic anemia (AA) is a rare disease with few reports on its ophthalmic manifestations. The ocular findings are described in a retrospective consecutive series of 719 AA Korean patients followed at the Hematology Clinic of The Catholic University of Korea. Out of a total of 719 patients, 269 patients had eye examinations, 156 patients had retinal evaluation, and 37 (23.7%) had retinal findings. These 37 patients had unilateral retinal hemorrhage in seven and bilateral retinal hemorrhage in 30 with mean hemoglobin of 6.6 g/dL (range 2.7-12.6 g/dL) and platelet counts of 18.8×10(9)/L (range 4-157×10(9)/L); central retinal vein occlusion-like picture occurred in nine patients and these had similar rheology to the rest of the subjects; optic disc edema, cotton-wool spots, macular edema, and dry eyes occurred in two, three, five, and three patients, respectively. In this Korean series of 141 subjects with AA, systemic bleeding occurred in 24.8% of subjects, retinal hemorrhage in 37% of subjects, and any bleeding site (eye or elsewhere) occurred in 47.5% of subjects with AA. A literature review (1958-2010) of 200 AA cases revealed retinal hemorrhages in 56%, subhyaloid or vitreous hemorrhage in 9%, peripheral retinal vasculopathy in 5.5%, and cotton-wool spots, Sjögrens syndrome, or optic disc edema in 4% each. The prevalence of retinopathy among series of AA patients varied from 20% to 28.3%, which is consistent with the Korean series of 24.8%. Management of AA patients needs to involve multiple specialties, including hematologists, ophthalmologists, and infectious disease specialists.

Impact of intravitreal triamcinolone acetonide versus intravitreal bevacizumab on retrobulbar hemodynamic in patients with diabetic macular edema

Abstract Purpose: To evaluate and compare retrobulbar hemodynamic changes measured with color Doppler imaging (CDI) in diabetic patients receiving intravitreal triamcinolone acetonide (IVTA) versus bevacizumab. Methods: Patients with diffuse diabetic macular edema were assessed prospectively by CDI following intravitreal injection of triamcinolone acetonide (group I, 12 eyes) versus bevacizumab (group II, 14 eyes). CDI was used to measure the peak systolic velocity (PSV), end diastolic velocity (EDV) and the resistive index (RI) of the central retinal artery (CRA), ophthalmic artery (OA) and posterior ciliary arteries (PCA) one day preoperatively and one week postoperatively. Results: In group I, EDV of OA and CRA decreased significantly (p = 0.007 and 0.018, respectively). The PSV and RI of PCA decreased significantly (p = 0.035 and 0.002, respectively). In group II, both the PSV and EDV of the CRA decreased significantly (p = 0.000). Comparing the percentage of change in both groups, PSV of the CRA decreased significantly in group II (p = 0.034), while IVTA has more significant effect on the ophthalmic artery hemodynamic parameters as EDV decreased and RI increased significantly (p = 0.045 and 0.043, respectively) Conclusion: Intravitreal injections of triamcinolone acetonide and bevacizumab have a significant effect on the ocular hemodynamic. The effect of bevacizumab is statistically significant on the PSV of CRA compared to IVTA.

A prospective, randomized comparison of intravitreal triamcinolone acetonide versus intravitreal bevacizumab (avastin) in diffuse diabetic macular edema

Purpose: To compare the functional and anatomical outcomes following intravitreal triamcinolone acetonide vs. intravitreal bevacizumab (Avastin) treatment for diffuse diabetic macular edema. Materials and Methods: In this prospective, randomized study, subjects were divided into two groups: 24 eyes that received intravitreal injection of 4 mg/0.1 mL triamcinolone acetonide (IVTA group) and 24 eyes received intravitreal injection of 1.25 mg/0.05 mL bevacizumab (IVB group). Changes in best corrected visual acuity (BCVA), intraocular pressure (IOP), baseline fluorescein angiography and optical coherence tomography measurements were evaluated in both groups. Follow-up visits out to three months from baseline are reported. Results: One month after treatment, baseline foveal thickness decreased from 452 µ to 299 µ in the IVTA group and from 292 µ to 270 µ in the IVB group. BCVA increased by two or more lines in 58.3% of eyes in the IVTA group and there was no similar improvement in the IVB group. In the IVTA group, a transient increase in IOP (27–43 mmHg) occurred in four cases (16.7%), which was successfully controlled with topical medications. There were no complications in the IVB group. Conclusion: Short term outcomes indicate that intravitreal injection of bevacizumab was not associated with surgical complications compared to triamcinolone acetonide. Triamcinolone acetonide appears to be more effective treatment for diabetic macular edema than bevacizumab.

Role of new magnetic resonance imaging modalities in diagnosis of orbital masses: a clinicopathologic correlation.

Purpose: To evaluate the role of diffusion-weighted magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) in the diagnosis of different orbital masses and their advantages over conventional MRI. Materials and Methods: The study included 20 patients presenting with proptosis. Every patient was subjected to thorough clinical examination, conventional MRI “T1 weighted, T2 weighted, and postcontrast T1 weighted if needed,” diffusion-weighted MRI, and proton MRS. Orbitotomy was performed, the orbital mass was excised, and histopathological examination was performed. Results: Diffusion-weighted MRI could differentiate between benign lesions and malignant tumors in 70% of cases; however, overlap occurred in 30% of cases with benign tumors showing restricted diffusion whereas proton MRS could differentiate between benign and malignant tumors in 90% of cases. Conclusion: Diffusion-weighted MRI and proton MRS can potentially increase the accuracy of diagnosis of orbital masses through in vivo tissue characterization. Magnetic resonance spectroscopy seems to be the more accurate modality.

Potential diagnostic value of fluorescein angiography and color Doppler imaging in primary open angle glaucoma

Purpose To evaluate absolute filling defects of the optic disc and color Doppler imaging (CDI) measurements in primary open angle glaucoma (POAG) to assess their diagnostic potentialities. Methods Twenty patients with POAG and 20 age- and sex-matched controls were included in this study. Fluorescein angiograms were performed and percentage of absolute fluorescein filling defects was calculated. Peak systolic velocity (PSV), end diastolic velocity (EDV), and resistive indices (RI) of the ophthalmic artery (OA), central retinal artery (CRA), and temporal and nasal short posterior ciliary arteries (TPCA, NPCA) were measured using CDI. Results Absolute filling defects of the optic nerve head and RI of CRA were significantly larger in patients with POAG (p<0.001). EDV of CRA, TPCA, and NPCA were significantly reduced in POAG (p<0.05). RI of OA, TPCA, and NPCA were significantly increased in patients with POAG (p<0.05). Absolute fluorescein filling defects percentages correlated with the RI of CRA and NPCA. They correlated negatively with EDV of CRA, NPCA, and TPCA. The diagnostic accuracy of the RI of CRA in glaucoma was 96% while that of absolute fluorescein filling defects percentages was 92%. Conclusions The combination of different techniques allows further interpretation of ocular circulatory changes in glaucoma and help in diagnosis of glaucoma. Further studies are needed for better understanding of the relationship between circulatory and neural loss.

Angiographic characteristics of central serous chorioretinopathy in an Egyptian population

AIM To describe and analyze the demographic characteristics and to determine the angiographic features of acute central serous chorioretinopathy(CSCR) in an Egyptian population. METHODS A series of consecutive patients presenting with acute idiopathic CSCR to Mansoura Ophthalmology Center Mansoura University who underwent fluorescein angiography (FA) within a 3-year-period (between January 1, 2007 and December 31, 2009) was retrospectively studied. Patient demographics and angiographic features were studied. Results were compared to those of other Western and Asian populations. RESULTS Fluorescein angiograms of 86 patients were analyzed. 91% were males. The age range of patients was 24 - 49 years, with a mean age of (38±6) years. The right eye was the presenting eye in 47% of patients. Eighty-seven percent of eyes showed delayed choroidal filling. Thirty-five percent of patients had more than one point of leakage. The macula was the most common site of fluorescein leakage seen in 79% of patients. Peripheral leakage was seen in 14% of patients while peripapillary leakage was seen in 12% of patients. The inkblot leakage pattern was found in 53% of patients. The presenting eye had RPE atrophic changes in 84% of cases. The other eye was assessed in 44 patients (51%). Fifty-five percent of them had signs of RPE atrophic changes. CONCLUSION In the Egyptian population, CSCR is seen at younger age with higher male-to-female ratio and more frequent smokestack leaks than other populations. Despite younger age group, this series of patient showed higher frequency of bilateral and multifocal disease compared to other studies. Roles of psychological stress and choroidal ischemia in pathogenesis of CSCR need further evaluation.

Anticardiolipin antibodies in proliferative diabetic retinopathy: An additional risk factor.

PURPOSE To report the prevalence of anticardiolipin antibodies in patients with proliferative diabetic retinopathy (PDR) having high-risk criteria (HRC). METHODS Diabetic patients having PDR with HRC and diabetics free of retinopathy were compared for the presence of anticardiolipin antibodies. RESULTS Among the 34 patients, 6 (17.7%) of diabetics having PDR with HRC were positive for anticardiolipin antibodies. There was no significant association of aCL antibodies with sex or type of diabetes. Using Pearsons correlation test, no significant associations of aCL antibodies with duration of diabetes or age of patients were found. All patients who were positive for anticardiolipin antibodies had PDR with HRC. The difference was statistically significant. CONCLUSION Presence of anticardiolipin antibodies may represent an additional risk factor for PDR.