High circulating levels of the hormone prolactin (PRL) protect against experimental diabetic retinopathy (DR) due to the retinal accumulation of vasoinhibin, a PRL fragment that inhibits blood vessel permeability and growth. A phase 2 clinical trial is investigating a new therapy for DR based on elevating serum PRL levels with levosulpiride, a prokinetic dopamine D2 receptor blocker. Here, we tested whether levosulpiride-induced hyperprolactinemia elevates PRL and vasoinhibin in the vitreous of volunteer patients with proliferative DR (PDR) undergoing elective pars plana vitrectomy. Methods: Patients were randomized to receive placebo (lactose pill, orally TID; n = 19) or levosulpiride (25 mg orally TID; n = 18) for the 7 days before vitrectomy. Vitreous samples from untreated non-diabetic (n = 10) and PDR (n = 17) patients were also studied. Results: Levosulpiride elevated the systemic (101 ± 13 [SEM] vs. 9.2 ± 1.3 ng/mL, P < 0.0001) and vitreous (3.2 ± 0.4 vs. 1.5 ± 0.2 ng/mL, P < 0.0001) levels of PRL, and both levels were directly correlated (r = 0.58, P < 0.0002). The vitreous from nondiabetic patients or from PDR patients treated with levosulpiride, but not from placebotreated PDR patients, inhibited the basic fibroblast growth factor (bFGF)-and vascular endothelial growth factor (VEGF)-induced proliferation of endothelial cells in culture. Vasoinhibin-neutralizing antibodies reduced the vitreous antiangiogenic effect. Matrix metalloproteases (MMPs) in the vitreous cleaved PRL to vasoinhibin, and their activity was higher in non-diabetic than in PDR patients. Conclusions: Levosulpiride increases the levels of PRL in the vitreous of PDR patients and promotes its MMP-mediated conversion to vasoinhibin, which can inhibit angiogenesis in DR. Translational Relevance: These findings support the potential therapeutic benefit of levosulpiride against vision loss in diabetes.

BackgroundDiabetic retinopathy (DR) and diabetic macular edema (DME) are potentially blinding, microvascular retinal diseases in people with diabetes mellitus. Preclinical studies support a protective role of the hormone prolactin (PRL) due to its ocular incorporation and conversion to vasoinhibins, a family of PRL fragments that inhibit ischemia-induced retinal angiogenesis and diabetes-derived retinal vasopermeability. Here, we describe the protocol of an ongoing clinical trial investigating a new therapy for DR and DME based on elevating the circulating levels of PRL with the prokinetic, dopamine D2 receptor blocker, levosulpiride.MethodsIt is a prospective, randomized, double-blind, placebo-controlled trial enrolling male and female patients with type 2 diabetes having DME, non-proliferative DR (NPDR), proliferative DR (PDR) requiring vitrectomy, and DME plus standard intravitreal therapy with the antiangiogenic agent, ranibizumab. Patients are randomized to receive placebo (lactose pill, orally TID) or levosulpiride (75 mg/day orally TID) for 8 weeks (DME and NPDR), 1 week (the period before vitrectomy in PDR), or 12 weeks (DME plus ranibizumab). In all cases the study medication is taken on top of standard therapy for diabetes, blood pressure control, or other medical conditions. Primary endpoints in groups 1 and 2 (DME: placebo and levosulpiride), groups 3 and 4 (NPDR: placebo and levosulpiride), and groups 7 and 8 (DME plus ranibizumab: placebo and levosulpiride) are changes from baseline in visual acuity, retinal thickness assessed by optical coherence tomography, and retinal microvascular abnormalities evaluated by fundus biomicroscopy and fluorescein angiography. Changes in serum PRL levels and of PRL and vasoinhibins levels in the vitreous between groups 5 and 6 (PDR undergoing vitrectomy: placebo and levosulpiride) serve as proof of principle that PRL enters the eye to counteract disease progression. Secondary endpoints are changes during the follow-up of health and metabolic parameters (blood pressure, glycated hemoglobin, and serum levels of glucose and creatinine). A total of 120 patients are being recruited.DiscussionThis trial will provide important knowledge on the potential benefits and safety of elevating circulating and intraocular PRL levels with levosulpiride in patients with DR and DME.Ethics and disseminationEthics approval has been obtained from the Ethics Committees of the National University of Mexico (UNAM) and the Instituto Mexicano de Oftalmología, I.A.P. Dissemination will include submission to peer-reviewed scientific journals and presentation at congresses.Clinical trial registrationRegistered at , ID: NCT03161652 on May 18, 2017.

Background Retinopathy of prematurity (ROP), the primary cause of blindness in children, is a potential complication for 7.7% of live births in Mexico. Given that less than one-third of all neonatal intensive care units follow Mexican National ROP guidelines, there have been few reports regarding the incidences of types 1 and 2 ROP. Methods This was a retrospective study that investigated the incidence and onset of ROP in a representative sample of children in Mexico. We analyzed the results obtained by the ROP Detection and Treatment Program, compliant with the Mexican National ROP guidelines, over a 1-year period. This study included 132 children who were born prematurely, were initially screened between October 2, 2017 and October 1, 2018, and underwent follow-up based on their risk group (in accordance with the Mexican National ROP guidelines). Results The mean gestational age (GA) at birth was 32 weeks and 3 days (32w3d) (95% CI, ± 3 days), and the mean birth weight (BW) was 1594 g (95% CI, ± 96 g). The clinical features were as follows: 36.4% had immature retina without ROP, 22.0% had mild ROP, 5.3% had type 2 ROP, 27.3% had type 1 ROP, and 1.5% had advanced disease. Premature children with ROP requiring treatment (i.e., type 1 ROP + advanced ROP) were born at an MGA of 30w4d (95% CI, ± 5d; range, 26–35 weeks); their MBW was 1316 g (95% CI, ± 110 g; range, 830–2220 g). Diagnosis of ROP requiring treatment was made at a mean postmenstrual age (PMA) of 37w3d (95% CI, ± 5d; range, 31w1d to 42w1d). Conclusion In Mexico, screening and close ophthalmological follow-up of children who present with risk factors of birth weight < 1750 g and gestational age ≤ 34 weeks, both of which are observed more frequently in children with type 1 ROP, appears essential for implementing timely treatments (within 72 h). This is particularly important for children with PMA between 36 and 38 weeks, which is considered to be the peak age for disease stages that require timely intervention.

Purpose: The purpose of the study is to describe visual and anatomic outcomes of 5774nm micropulse laser photocoagulation in eyes with either treatment-naïve or refractory diabetic macular edema (DME) at 3 months. Methods: This was a prospective case series that recruited 23 consecutive patients (33 eyes) with center-involved DME that was either treatment-naïve or had not responded to prior treatment. Micropulse therapy was performed with the Easy Ret 577 (Quantel Medical, Cournon d’Auvergne, France) diode laser in a high-density manner in eyes with treatment-naïve or refractory DME. The primary outcome was the change of best-corrected visual acuity (BCVA; logMAR) at 1 and 3 months. Secondary outcomes were changes in the central macular thickness (CMT), thickness area, macular volume, and macular capillary leakage at 1 and 3 months. Results: There were no significant changes in BCVA at 3 months, with mean ± standard deviation (SD) of −0.08 ± 0.01 ( p = 0.228) and + 0.01 ± 0.01 ( p = 0.969) for treatment-naïve and refractory groups, respectively. The change in CMT at 3 months was statistically but not clinically significant in the treatment-naïve group only (mean ± SD; –30 ± 130 µm; p = 0.011). The macular volume and area thickness change were not statistically significant ( p = 0.173 and p = 0.148 for macular volume and area thickness, respectively) in the treatment-naïve group. There was no difference concerning the leakage area in both groups. No adverse events were reported. Conclusion: We concluded that micropulse 577nm laser therapy maintained the visual acuity and macular thickness at 3 months in both treatment-naïve and refractory DME.

Précis: Intraocular pressure (IOP) measurement differences with Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT) are affected by atmospheric pressure inside a hyperbaric chamber. Purpose: To compare IOP measurements obtained with GAT and DCT in 22 normal individuals at different atmospheric pressures simulated in a hyperbaric chamber. Methods: The IOP of both eyes of 22 healthy volunteers was measured using GAT and DCT at 4 different atmospheric pressure levels. Starting at 1 Queretaro atmospheric pressure (QATM), the IOP was measured with GAT and DCT. The atmospheric pressure was then increased to 1.1 QATM (equivalent to 1032 m above sea level), 1.2 QATM (equivalent to 315 m above sea level), and 1.25 QATM (equivalent to sea level), starting 5 minutes after reaching each level. The limits of agreement between various measurements with each tonometer were calculated using the Bland-Altman plots. Results: The first 4 subjects were used to measure feasibility, consistency, variability, and the time needed for IOP to return to baseline after each atmospheric pressure increase. For the entire 44 eyes, the mean GAT IOP at 1 QATM was 12.23 mm Hg (range, 8 to 20 mm Hg; SD, 2.84) and mean DCT was 16.36 (range, 12.1 to 25.3; SD, 2.84), with a mean 4.14 mm Hg difference (range, −0.1 to 7.5 mm Hg; SD, 1.62; P<0.001). Using the second measurements of the first 4 subjects and those after 5 minutes of adaptation for the rest of the group at 1.1 QATM, mean GAT IOP was 11.05±2.68 mm Hg and mean DCT IOP was 15.60±3.02 mm Hg, for a mean difference between instruments of 4.56±1.81 mm Hg (P<0.001). At 1.2 QATM, mean GAT IOP was 11.14±2.53 mm Hg and mean DCT IOP was 15.39±2.91 mm Hg. The difference between instruments was 4.25±2.12 mm Hg (P<0.001). At 1.25 QATM, the mean GAT IOP was 12.39±3.11 mm Hg and mean DCT IOP was 14.91±2.73 mm Hg. The difference between instruments after 5 minutes of adaptation was 2.53±1.62 mm Hg (P<0.001). Generalized estimating equations for performing linear regression multivariable analysis using atmospheric pressure, expressed as altitude, and age as covariates, shows that the difference between GAT and DCT increases by 1 mm Hg per 673 m of increase of altitude above sea level. Age was not a significant predictor. Conclusions: Acute changes in atmospheric pressure induce changes in IOP measurements for both GAT and DCT and in different directions. Despite the limitation of sample size, it may be postulated that the difference of IOP measurements between the 2 tonometers increases with lower atmospheric pressures.