A randomized, double-masked controlled clinical trial of Sandostatin long-acting release depot in patients with postsurgical cystoid macular edema

Somatostatin analogues as a treatment option for cystoid maculopathy in retinitis pigmentosa

AIMS

This study aimed to evaluate the effectiveness of somatostatin analogues (SA) for cystoid maculopathy (CM) in retinitis pigmentosa (RP) patients.

MATERIALS AND METHODS

In this retrospective case series, clinical and imaging characteristics of 28 RP patients with CM, unresponsive to carbonic anhydrase inhibitors, were collected from medical charts. All patients received SA treatment as an alternative (octreotide long-acting release at 20 mg/month or 30 mg/month, or lanreotide at 90 mg/month or 120 mg/month). Outcome measures were mean reduction in foveal thickness (FT) and foveal volume (FV) and mean increase in best-corrected visual acuity at 3, 6 and 12 months of treatment initiation. Linear mixed models were used to calculate the effectiveness over time.

RESULTS

52 eyes of 28 RP patients were included; 39% were male. The median age at the start of treatment was 39 years (IQR 30-53). Median follow-up was 12 months (range 6-12). From baseline to 12 months, the mean FT decreased from 409±136 µm to 334±119 µm and the mean FV decreased from 0.31±0.10 mm3 to 0.25±0.04 mm3. Linear mixed model analyses showed a significant decrease in log FT and log FV at 3, 6 and 12 months after the start of treatment compared with baseline measurements (p<0.001, p<0.001, p<0.001). Mean best-corrected visual acuity did not increase significantly (0.46±0.35 logMAR to 0.45±0.38 logMAR after 12 months).

DISCUSSION

SA may be an effective alternative treatment to reduce CM in RP patients.

Current management options for the treatment of refractory postoperative cystoid macular edema: A systematic review

Post-operative cystoid macular edema (PCME) is an important complication following intraocular surgery that often resolves spontaneously without treatment. In some cases, PCME may persist despite initial medical therapy, which can adversely impact visual outcomes. Various topical, intraocular and systemic treatments exist for the prevention and management of cystoid macular edema; however, there is no consensus on treatment of refractory cases in the postoperative setting. In accordance with the PRISMA guidelines, we systematically reviewed 68 articles describing management options and their outcomes for treatment-resistant cases of PCME. The most commonly reported treatments included steroid (39 studies) and biological-based (17 studies) therapies. We provide an overview of the treatment options for refractory PCME.

Spermine oxidase: A promising therapeutic target for neurodegeneration in diabetic retinopathy

Diabetic Retinopathy (DR), is a significant public health issue and the leading cause of blindness in working-aged adults worldwide. The vision loss associated with DR affects patients' quality of life and has negative social and psychological effects. In the past, diabetic retinopathy was considered as a vascular disease; however, it is now recognized to be a neuro-vascular disease of the retina. Current therapies for DR, such as laser photocoagulation and anti-VEGF therapy, treat advanced stages of the disease, particularly the vasculopathy and have adverse side effects. Unavailability of effective treatments to prevent the incidence or progression of DR is a major clinical problem. There is a great need for therapeutic interventions capable of preventing retinal damage in DR patients. A growing body of evidence shows that neurodegeneration is an early event in DR pathogenesis. Therefore, studies of the underlying mechanisms that lead to neurodegeneration are essential for identifying new therapeutic targets in the early stages of DR. Deregulation of the polyamine metabolism is implicated in various neurodegenerative diseases, cancer, renal failure, and diabetes. Spermine Oxidase (SMOX) is a highly inducible enzyme, and its dysregulation can alter polyamine homeostasis. The oxidative products of polyamine metabolism are capable of inducing cell damage and death. The current review provides insight into the SMOX-regulated molecular mechanisms of cellular damage and dysfunction, and its potential as a therapeutic target for diabetic retinopathy. Structural and functional changes in the diabetic retina and the mechanisms leading to neuronal damage (excitotoxicity, loss of neurotrophic factors, oxidative stress, mitochondrial dysfunction etc.) are also summarized in this review. Furthermore, existing therapies and new approaches to neuroprotection are discussed.

Current Advances in Pharmacotherapy and Technology for Diabetic Retinopathy: A Systematic Review

Diabetic retinopathy (DR) is classically defined by its vascular lesions and damage in the neurons of the retina. The cellular and clinical elements of DR have many features of chronic inflammation. Understanding the individual cell-specific inflammatory changes in the retina may lead to novel therapeutic approaches to prevent vision loss. The systematic use of available pharmacotherapy has been reported as a useful adjunct tool to laser photocoagulation, a gold standard therapy for DR. Direct injections or intravitreal anti-inflammatory and antiangiogenesis agents are widely used pharmacotherapy to effectively treat DR and diabetic macular edema (DME). However, their effectiveness is short term, and the delivery system is often associated with adverse effects, such as cataract and increased intraocular pressure. Further, systemic agents (particularly hypoglycemic, hypolipidemic, and antihypertensive agents) and plants-based drugs have also provided promising treatment in the progression of DR. Recently, advancements in pluripotent stem cells technology enable restoration of retinal functionalities after transplantation of these cells into animals with retinal degeneration. This review paper summarizes the developments in the current and potential pharmacotherapy and therapeutic technology of DR. Literature search was done on online databases, PubMed, Google Scholar, clinitrials.gov, and browsing through individual ophthalmology journals and leading pharmaceutical company websites.

Silicon micro- and nanofabrication for medicine

This manuscript constitutes a review of several innovative biomedical technologies fabricated using the precision and accuracy of silicon micro- and nanofabrication. The technologies to be reviewed are subcutaneous nanochannel drug delivery implants for the continuous tunable zero-order release of therapeutics, multi-stage logic embedded vectors for the targeted systemic distribution of both therapeutic and imaging contrast agents, silicon and porous silicon nanowires for investigating cellular interactions and processes as well as for molecular and drug delivery applications, porous silicon (pSi) as inclusions into biocomposites for tissue engineering, especially as it applies to bone repair and regrowth, and porous silica chips for proteomic profiling. In the case of the biocomposites, the specifically designed pSi inclusions not only add to the structural robustness, but can also promote tissue and bone regrowth, fight infection, and reduce pain by releasing stimulating factors and other therapeutic agents stored within their porous network. The common material thread throughout all of these constructs, silicon and its associated dielectrics (silicon dioxide, silicon nitride, etc.), can be precisely and accurately machined using the same scalable micro- and nanofabrication protocols that are ubiquitous within the semiconductor industry. These techniques lend themselves to the high throughput production of exquisitely defined and monodispersed nanoscale features that should eliminate architectural randomness as a source of experimental variation thereby potentially leading to more rapid clinical translation.

Vitreous levels of somatostatin in patients with chronic uveitic macular oedema

PURPOSE

Intravitreal somatostatin (SST) levels are decreased in patients with diabetic macular oedema. This deficit may be involved in the pathogenesis of this condition. The aim of the present study was to determine SST concentration in the vitreous fluid of patients with chronic uveitic macular oedema (CUMO) and quiescent intraocular inflammation.

METHODS

Plasma and vitreous fluid samples were obtained during vitrectomy from 11 eyes of patients with CUMO and from 42 eyes of control subjects (idiopathic epiretinal membrane, macular hole). SST concentration was measured by radioimmunoassay.

STATISTICS

χ(2)-square test, Mann-Whitney U-test, Wilcoxon test, Spearman's rank correlation coefficient, and multivariant linear regression models.

RESULTS

Plasma SST concentrations were similar in uveitic patients and controls (28.25 pg/ml (21.3-31) vs 28.7 pg/ml (22-29.5); P=0.869). A higher vitreous concentration of proteins was found in uveitic patients (1.59±0.38 mg/ml vs 0.73±0.32 mg/ml, P<0.0001). Vitreous SST was markedly lower in uveitic patients, both in absolute terms and after adjusting for total intravitreous protein concentration (39.37 pg/ml (6.16-172) vs 486.73 pg/ml (4.7-1833), P<0.0001; 33.1 pg/mg (3.9-215.74) vs 629.75 pg/mg (6.91-2024), P<0.0001). No correlations were found between plasma and vitreous concentration of SST in either group (ρ=0.191, P=0.57 and ρ=0.49, P=0.66). There were no correlations between vitreous SST concentration and visual acuity or macular thickness in uveitic patients (ρ=0.302, P=0.31 and ρ=0.45, P=0.13).

CONCLUSIONS

Intravitreous SST is decreased in patients with CUMO and quiescent intraocular inflammation. The deficit of SST may have a role in the pathogenesis of this condition.