INTRAVITREAL CLINDAMYCIN FOR TOXOPLASMIC RETINOCHOROIDITIS

Considerations in the management of ocular toxoplasmosis in pregnancy: a review of literature

Ocular toxoplasmosis is the most common cause of infectious posterior uveitis. Available literature is still conflicting regarding the incidence of recurrence during pregnancy as various calculations were employed in the different published studies. Although earlier reports have suggested a difference in presentation and an increase in severity during pregnancy, newer studies appear to show otherwise. Further diagnostic testing, including serologic and intraocular fluid sampling, may be indicated to increase the diagnostic accuracy in this special population of patients. The management of ocular toxoplasmosis during pregnancy is challenging as the foetus is additionally considered in the choice of treatment. Traditionally preferred anti-toxoplasmosis regimens containing antifolate drugs, such as pyrimethamine and trimethoprim-sulfamethoxazole, cannot be used routinely in pregnant patients, especially during the first trimester. This review includes literature on alternative treatments for ocular toxoplasmosis during pregnancy, including spiramycin and intravitreal treatment options.

TOXOPLASMOSIS RETINOCHOROIDITIS MASQUERADING AS ENDOGENOUS ENDOPHTHALMITIS IN A CASE OF CONGENITAL LONG QT SYNDROME

PURPOSE

To describe the diagnostic and treatment challenges of a case of presumed acquired macula-involving toxoplasmosis retinochoroiditis.

METHODS

Case report of a woman with congenital long QT syndrome presenting with retinochoroiditis after undergoing a cardiac procedure. Laboratory analysis, ocular fluid biopsy, and multimodal imaging were obtained.

RESULTS

Ophthalmic examination was significant for decreased vision and a macula-involving chorioretinal lesion concerning for endogenous endophthalmitis. Multimodal imaging showed a focal, full-thickness necrotizing process associated with vitritis, retinal edema, and choroidal thickening. Analysis of peripheral blood revealed elevated serum toxoplasma Immunoglobulin G titers. Blood cultures and a transesophageal echocardiogram were negative for endocarditis. Aqueous and vitreous specimens were negative for an infectious polymerase chain reaction panel, including toxoplasmosis and negative bacterial and fungal cultures. A diagnosis of presumed acquired toxoplasmosis retinochoroiditis was made and treated with a combination of oral and intravitreal antiparasitic medications resulting in healing of the retinochoroiditis.

CONCLUSION

To the authors' knowledge, this is the first reported case of acquired toxoplasmosis retinochoroiditis in an immunocompetent patient with congenital long QT syndrome masquerading as endogenous endophthalmitis. The association of congenital long QT syndrome and a recent cardiac procedure with a risk for endogenous endophthalmitis complicated the diagnosis, clinical course, and treatment options. Our case emphasizes the importance of a thorough patient history, comprehensive clinical examination, and supportive multimodal imaging that were used to characterize the infectious process and guide empirical treatment. In addition, laboratory analysis, comanagement with other specialists, and evaluating the response to antitoxoplasma therapy were all instrumental in the eventual diagnosis and treatment of ocular toxoplasmosis in this atypical case.

Macular Infarction following Intravitreal Clindamycin Injection : A Case Report

Purpose

To report a case of Toxoplasma retinochoroiditis that was complicated by macular infarction following intravitreal clindamycin injection.

Methods

A 32-year-old otherwise healthy woman with the diagnosis of reactivation of Toxoplasma retinochoroiditis in her right eye, underwent intravitreal clindamycin injection. Shortly after injection, the visual acuity deteriorated, and the fundus examination revealed an extensive area of macular necrosis accompanied by vascular occlusion.

Results

The patient was observed. Unfortunately, the condition did not improve over time and resulted in a large area of retinal atrophy.

Conclusion

Macular infarction should be considered a rare but disastrous complication that can result in severe, irreversible visual loss.

[Intravitreal clindamycin injection in toxoplasma retinochoroiditis: About 9 cases in the ophthalmology department of the CHU de Bordeaux]

INTRODUCTION

Toxoplasma retinochoroiditis (TRC) is the main cause of posterior uveitis in immunocompetent patients. Several studies have shown safety and efficacy of treatment with intravitreal clindamycin injection in patients with contraindications, inadequate response or side effects with classic oral therapy. The goal of this study is to describe anatomic and functional results of local treatment with intravitreal clindamycin injection.

MATERIALS AND METHODS

We performed an observational, retrospective, single-center study in the ophthalmology service of Bordeaux university medical center between December 2017 and January 2020 on management of toxoplasma retinochoroiditis by intravitreal clindamycin injection. We analyzed the efficacy of this treatment on improvement in visual acuity, decrease in size of the retinal lesion and decrease in macular thickness.

RESULTS

A total of 10 eyes of 9 patients were injected. Only a single injection was required in 9 of the 10 cases. Injections demonstrated improvement in the 3 study criteria; visual acuity went from a mean of 1 LogMAR (1.07±0.77) pre-injection to 0.4 LogMAR (0.43±0.53) at 6 months, lesion size decreased by 51%, and macular thickness decreased by 78μm over the follow-up period.

CONCLUSION

Intravitreal clindamycin injections are safe and effective for the treatment of TRC. They offer an alternative in patients with allergies, side effects or inadequate response to classic oral therapy.

<p>Intravitreal Clindamycin as First-Line Therapy for Toxoplasmic Retinochoroiditis: A Case Series</p>

Purpose

Materials and Methods

Results

Conclusion

Antimicrobial guide to posterior segment infections

PURPOSE

This review article is meant to serve as a reference guide and to assist the treating physician in making an appropriate selection and duration of an antimicrobial agent.

METHODS

Literature review.

RESULTS

Infections of the posterior segment require prompt medical or surgical therapy to reduce the risk of permanent vision loss. While numerous options exist to treat these infections, doses and alternative therapies, especially with contraindications for first-line therapy, are often elusive. Antimicrobial agents to treat posterior segment infections can be administered via various routes, including topical, intravitreal, intravenous, and oral.

CONCLUSIONS

Although there are many excellent review articles on the management of endophthalmitis, we take the opportunity in this review to comprehensively summarize the appropriate antimicrobial regimen of both common and rare infectious etiologies of the posterior segment, using evidence from clinical trials and large case series.

Intravitreal clindamycin as a therapeutic alternative in severe ocular toxoplasmosis

Ocular toxoplasmosis is a disease than have severe consequences on the eyesight. The aim of this study article is to present a bilateral ocular toxoplasmosis in a sulfamide allergic patient with unilateral activation and her favourable progression with intravitreal Clindamycin and oral steroids treatment. Weekly intravitreal Clindamycin treatment is shown to be a suitable therapeutic alternative in cases of severe ocular toxoplasmosis and/or in patients with a contraindication to classical treatment. Intravitreal Clindamycin treatment is a safe alternative with favourable clinical results.

Ocular Toxoplasmosis in a Tertiary Referral Center in Sydney Australia-Clinical Features, Treatment, and Prognosis

PURPOSE

The aim of this study was to provide a retrospective analysis of the presentation, demographics, and treatment regimens for ocular toxoplasmosis at a large tertiary referral uveitis center.

DESIGN

Retrospective cohort study.

PARTICIPANTS

A total of 48 patients with ocular toxoplasmosis who presented to Sydney Eye Hospital participated in this study.

METHODS

This is a retrospective review of patient files who presented to Sydney Eye Hospital between 2007 and 2016 with clinical features consistent with ocular toxoplasmosis. Baseline risk factors and treatment details were recorded and analyzed. Main outcome measures were visual acuity and relapse rate compared with other studies in ocular toxoplasmosis.

RESULTS

The median age was 35.5 (interquartile range 21-50) with 30 (60%) patients having no previous symptomatic episodes or evidence of chorioretinal scarring. Visual acuity at presentation was 0.51 or 6/19 (SE 0.096) and at follow-up 0.31 or 6/12 (SE 0.094). Nine patients experienced a recurrence during the period of observation with median time to recurrence 2.2 years (SE 0.45) and the relapse rate was 0.09/person-years. Location of lesion was predominantly within the vascular arcades (n = 44) with macular involvement in 9 patients. Most patients received clindamycin therapy (n = 34) with pyrimethamine and sulfadiazine was used for those with macula involvement.

CONCLUSIONS

Patients with ocular toxoplasmosis had fewer recurrences compared with other published series and had better visual recovery. The majority of patients received clindamycin and oral prednisolone which were well tolerated with pyrimethazine and sulfadiazine reserved for those with macula-involving disease.

Treatment of Toxoplasmosis: Historical Perspective, Animal Models, and Current Clinical Practice

Primary Toxoplasma gondii infection is usually subclinical, but cervical lymphadenopathy or ocular disease can be present in some patients. Active infection is characterized by tachyzoites, while tissue cysts characterize latent disease. Infection in the fetus and in immunocompromised patients can cause devastating disease. The combination of pyrimethamine and sulfadiazine (pyr-sulf), targeting the active stage of the infection, is the current gold standard for treating toxoplasmosis, but failure rates remain significant. Although other regimens are available, including pyrimethamine in combination with clindamycin, atovaquone, clarithromycin, or azithromycin or monotherapy with trimethoprim-sulfamethoxazole (TMP-SMX) or atovaquone, none have been found to be superior to pyr-sulf, and no regimen is active against the latent stage of the infection. Furthermore, the efficacy of these regimens against ocular disease remains uncertain. In multiple studies, systematic screening for Toxoplasma infection during gestation, followed by treatment with spiramycin for acute maternal infections and with pyr-sulf for those with established fetal infection, has been shown to be effective at preventing vertical transmission and minimizing the severity of congenital toxoplasmosis (CT). Despite significant progress in treating human disease, there is a strong impetus to develop novel therapeutics for both the acute and latent forms of the infection. Here we present an overview of toxoplasmosis treatment in humans and in animal models. Additional research is needed to identify novel drugs by use of innovative high-throughput screening technologies and to improve experimental models to reflect human disease. Such advances will pave the way for lead candidates to be tested in thoroughly designed clinical trials in defined patient populations.

Intravitreal Clindamycin and Dexamethasone Combined with Systemic Oral Antitoxoplasma Therapy versus Intravitreal Therapy Alone in the Management of Toxoplasma Retinochoroiditis: A Retrospective Study

Purpose

To compare clinical outcome of IVCD combined with oral therapy with IVCD alone in patients with toxoplasmic retinochoroiditis.

Patients and Methods

Thirty eyes were reviewed. Two equal groups were identified (15 eyes each). Clinical outcome measures were resolution of active inflammation, changes in BCVA and CMT, adverse drug reactions, and rate of recurrence.

Results

Mean baseline of BCVA 1.08 ± 0.17 and 1.03 ± 0.15 improved to 0.64 ± 0.18 and 0.69 ± 0.17 at the end of follow-up in group I and II, respectively. No statistically significant difference was observed. CMT was 392.6 ± 33.16 μm and 397.3 ± 14.6 μm significantly decreased to 314.7 ± 4.43 μm and 319.6 ± 7.8 μm. Resolution of acute inflammation was achieved in all cases in both groups. There were no recurrent cases in group I, and only one out of 15 (6.7%) in group II. No ocular or systemic adverse events were recorded.

Conclusion

IVCD is an effective route of treatment for active toxoplasmic retinochoroiditis that can be used solely without the need to use systemic medications..

Safety of intravitreal clindamycin in albino rabbit eyes

PURPOSE

To study the potential toxic effects of intravitreal clindamycin on the retina of albino rabbits, by assessing functional and morphological retinal changes.

METHODS

Eight albino rabbits were included in the study. In each rabbit, 1 mg/0.1 ml clindamycin was injected into the vitreous of the right (experimental) eye, and 0.1 ml saline was injected into the vitreous of the left (control) eye. The electroretinogram (ERG) was recorded before injection, 3 days, 1, 2, and 4 weeks post-injection. The visual evoked potential (VEP) was recorded 4 weeks post-injection. Clinical examination was conducted at all time points. The eyes were enucleated at the termination of the follow-up period in order to prepare the retinas for histology in order to assess retinal structure.

RESULTS

ERG and VEP responses that were recorded from the experimental eye at different times following intravitreal clindamycin injection were very similar to the corresponding responses that were recorded from the control eyes. Clinical examination was normal in all eyes, and no histological damage was observed.

CONCLUSIONS

Intravitreal injection of 1 mg clindamycin does not cause functional or morphological signs of retinal toxicity in albino rabbits, during a period of 4 weeks post-injection. These findings support the clinical use of 1 mg intravitreal clindamycin.

Ocular safety of Intravitreal Clindamycin Hydrochloride Released by PLGA Implants

BACKGROUND

Drug ocular toxicity is a field that requires attention. Clindamycin has been injected intravitreally to treat ocular toxoplasmosis, the most common cause of eye posterior segment infection worldwide. However, little is known about the toxicity of clindamycin to ocular tissues. We have previously showed non intraocular toxicity in rabbit eyes of poly(lactic-co-glycolic acid) (PLGA) implants containing clindamycin hydrochloride (CLH) using only clinical macroscotopic observation. In this study, we investigated the in vivo biocompatibility of CLH-PLGA implants at microscotopic, cellular and molecular levels.

METHODS

Morphology of ARPE-19 and MIO-M1 human retinal cell lines was examined after 72 h exposure to CLH-PLGA implant. Drug delivery system was also implanted in the vitreous of rat eyes, retinal morphology was evaluated in vivo and ex vivo. Morphology of photoreceptors and inflammation was assessed using immunofluorescence and real-time PCR.

RESULTS

After 72 h incubation with CLH-PLGA implant, ARPE-19 and MIO-M1 cells preserved the actin filament network and cell morphology. Rat retinas displayed normal lamination structure at 30 days after CLH-PLGA implantation. There was no apoptotic cell and no loss in neuron cells. Cones and rods maintained their normal structure. Microglia/macrophages remained inactive. CLH-PLGA implantation did not induce gene expression of cytokines (IL-1β, TNF-α, IL-6), VEGF, and iNOS at day 30.

CONCLUSION

These results demonstrated the safety of the implant and highlight this device as a therapeutic alternative for the treatment of ocular toxoplasmosis.

Current Practices in Ocular Toxoplasmosis: A Survey of Brazilian Uveitis Specialists

PURPOSE

To describe treatment practices for ocular toxoplasmosis among members of the Brazilian Uveitis Society.

METHODS

An online questionnaire sent to specialists, between October 2014 and March 2015.

RESULTS

Most respondents (67.9%) treat all active cases. Most specialists consider visual acuity <20/200 (88.2%), severe vitreous inflammation (94.1%), and ocular disease during acquired infection (88.2%) as absolute indications for treatment. Systemic steroids are associated with anti-toxoplasmic therapy in most cases by 50.9% of the respondents. For immunocompetent individuals, 57.4% of the respondents chose trimethoprim/sulfamethoxazole. Classical therapy (sulfadiazine/pyrimethamine) is preferred most for patients with central lesions (70.4%), immunosuppression (68.4%), acquired infection (70.4%), and atypical forms (74.1%). For patients with frequent relapses, 84.9% of the respondents preferred antibiotic prophylaxis.

CONCLUSIONS

Treatment patterns of ocular toxoplasmosis are not uniform among Brazilian specialists. Most specialists treat all cases of active retinochoroiditis. Typical cases are more frequently treated with trimethoprim/sulfamethoxazole. However, classical therapy is the regimen of choice when lesions are considered more severe.

Host and Toxoplasma gondii genetic and non-genetic factors influencing the development of ocular toxoplasmosis: A systematic review

Toxoplasmosis is a cosmopolitan infection caused by the apicomplexan parasite Toxoplasma gondii. This infectious disease is widely distributed across the world where cats play an important role in its spread. The symptomatology caused by this parasite is diverse but the ocular affectation emerges as the most important clinical phenotype. Therefore, we conducted a systematic review of the current knowledge of ocular toxoplasmosis from the genetic diversity of the pathogen towards the treatment available for this infection. This review represents an update to the scientific community regarding the genetic diversity of the parasite, the genetic factors of the host, the molecular pathogenesis and its association with disease, the available diagnostic tools and the available treatment of patients undergoing ocular toxoplamosis. This review will be an update for the scientific community in order to encourage researchers to deploy cutting-edge investigation across this field.

Anti-Toxoplasma activity and impact evaluation of lyophilization, hot molding process, and gamma-irradiation techniques on CLH-PLGA intravitreal implants

Intraocular delivery systems have been developed to treat many eye diseases, especially those affecting the posterior segment of the eye. However, ocular toxoplasmosis, the leading cause of infectious posterior uveitis in the world, still lacks an effective treatment. Therefore, our group developed an intravitreal polymeric implant to release clindamycin, a potent anti-Toxoplasma antibiotic. In this work, we used different techniques such as differential scanning calorimetry, thermogravimetry, X-ray diffraction, scanning electron microscopy, and fourier-transform infrared spectroscopy to investigate drug/polymer properties while manufacturing the delivery system. We showed that the lyophilization, hot molding process, and sterilization by gamma irradiation did not change drug/polymer physical-chemistry properties. The drug was found to be homogeneously dispersed into the poly lactic-co-glycolic acid (PLGA) chains and the profile release was characterized by an initial burst followed by prolonged release. The drug profile release was not modified after gamma irradiation and non-covalent interaction was found between the drug and the PLGA. We also observed the preservation of the drug activity by showing the potent anti-Toxoplasma effect of the implant, after 24-72 h in contact with cells infected by the parasite, which highlights this system as an alternative to treat toxoplasmic retinochoroiditis.

Current Therapy of Acquired Ocular Toxoplasmosis: A Review

Caused by the parasite Toxoplasma gondii, ocular toxoplasmosis (OT) is the most common form of posterior infectious uveitis. Combined antiparasitic therapy is the standard treatment for OT, but several other schemes have been proposed. The purpose of the present study was to review the literature on the treatment of OT and provide ophthalmologists with up-to-date information to help reduce OT-related visual morbidity. In conclusion, no ideal treatment scheme was identified; currently prescribed therapeutic schemes yield statistically similar functional outcomes.

Thermoanalytical characterization of clindamycin-loaded intravitreal implants prepared by hot melt extrusion

BACKGROUND

The aim of the present study was to evaluate a non-destructive fabrication method in for the development of sustained-release poly (L, D-lactic acid)-based biodegradable clindamycin phosphate implants for the treatment of ocular toxoplasmosis.

MATERIALS AND METHODS

The rod-shaped intravitreal implants with an average length of 5 mm and a diameter of 0.4 mm were evaluated for their physicochemical parameters. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR), and nuclear magnetic resonance (1H NMR) studies were employed in order to study the characteristics of these formulations.

RESULTS

Drug content uniformity test confirmed the uniformity in different implant batches. Furthermore, the DSC, FTIR, and 1H NMR studies proved that the fabrication process did not have any destructive effects either on the drug or on the polymer structures.

CONCLUSION

These studies showed that the developed sustained-release implants could be of interest for long-term sustained intraocular delivery of clindamycin, which can provide better patient compliance and also have good potential in terms of industrial feasibility.

Design and development of intraocular polymeric implant systems for long-term controlled-release of clindamycin phosphate for toxoplasmic retinochoroiditis

BACKGROUND

The release of the anti-toxoplasmosis drug, clindamycin phosphate, from intraocular implants of the biodegradable polymers poly (D, L-lactic acid) (PLA) and poly (D, L-lactide-co-glycolide) (PLGA) has been studied in vitro.

MATERIALS AND METHODS

The preparation of the implants was performed by a melt-extrusion method. The developed extrudates were characterized and compared in in-vitro release profiles for elucidating the drug release mechanism. The formulations containing up to 40% w/w of drug were prepared. Release data in phosphate buffer (pH 7.4) were analyzed by high performance liquid chromatography. The release kinetics were fitted to the zero-order, Higuchi's square-root, first order and the Korsmeyer-Peppas empirical equations for the estimation of various parameters of the drug release curves. Degradation of implants was also investigated morphologically with time (Scanning Electron Microscopy).

RESULTS

It was observed that, the release profiles for the formulations exhibit a typical biphasic profile for bulk-eroding systems, characterized by a first phase of burst release (in first 24 hrs), followed by a phase of slower release. The duration of the secondary phase was found to be proportional to the molecular weight and monomer ratio of copolymers and also polymer-to-drug ratios. It was confirmed that Higuchi and first-order kinetics were the predominant release mechanisms than zero order kinetic. The Korsmeyer-Peppas exponent (n) ranged between 0.10 and 0.96. This value, confirmed fickian as the dominant mechanism for PLA formulations (n ≤ 0.45) and the anomalous mechanism, for PLGAs (0.45 < n < 0.90).

CONCLUSION

The implant of PLA (I.V. 0.2) containing 20% w/w of clindamycin, was identified as the optimum formulation in providing continuous efficient in-vitro release of clindamycin for about 5 weeks.

Intravitreal clindamycin in the treatment of unresponsive zone one toxoplasmic chorioretinitis: a case report

Introduction:

The current study aimed to report a case of toxoplasma chorioretinitis resistant to standard treatments that dramatically responded to intravitreal clindamycin injection.

Case Presentation:

A 23-year-old woman with the diagnosis of ocular toxoplasmosis in the left eye was initially treated by oral pyrimethamine, sulfadiazine, azithromycin and oral prednisolone. Since the treatment was unsuccessful intravitreal clindamycin (1 mg/ 0.1 mL) was injected. Responding dramatically, visual acuity improved from hand motion to 20/60 and 20/20, after seven days and six weeks, respectively. Anterior chamber and vitreous reactions were resolved.

Conclusions:

Intravitreal injection of clindamycin may be an acceptable alternative to the classic treatment in cases with refractory ocular toxoplasmosis. It may offer the patient more convenience, a safer systemic side effect profile, greater availability, and fewer follow-up visits and hematologic evaluations. Moreover, since it responds dramatically, it would be helpful in cases with involvement of macula or closeness to the optic nerve.

Development of a method to quantify clindamycin in vitreous humor of rabbits' eyes by UPLC-MS/MS: application to a comparative pharmacokinetic study and in vivo ocular biocompatibility evaluation

Ocular toxoplasmosis may result in uveitis in the posterior segment of the eye, leading to severe visual complications. Clindamycin-loaded poly(lactide-co-glycolide) (PLGA) implants could be applied to treat the ocular toxoplasmosis. In this study, the pharmacokinetic profiles of the drug administrated by PLGA implants and by intravitreal injections in rabbits' eyes were evaluated. The implant released the drug for 6 weeks while the drug administrated by intravitreal injections remained in the vitreous cavity for 2 weeks. Compared to the injected drug, the implants containing clindamycin had higher values of area under the curve (AUC) (39.2 vs 716.7 ng week mL(-1)) and maximum vitreous concentration (Cmax) (8.7 vs 13.83 ng mL(-1)). The implants prolonged the delivery of clindamycin and increased the contact of the drug with the eyes' tissues. Moreover, the in vivo ocular biocompatibility of the clindamycin-loaded PLGA implants was evaluated regarding to the clinical examination of the eyes and the measurement of the intraocular pressure (IOP) during 6 weeks. The implantable devices caused no ocular inflammatory process and induced the increase of the IOP in the fourth week of the study. The IOP augmentation could be related to the maximum concentration of clindamycin released from the implants. In conclusion, the PLGA implants based on clindamycin may be a therapeutic alternative to treat ocular toxoplasmosis.

Current treatment of toxoplasma retinochoroiditis: an evidence-based review

Objective. To perform an evidence-based review of treatments for Toxoplasma retinochoroiditis (TRC). Methods. A systematic literature search was performed using the PubMed database and the key phrase "ocular toxoplasmosis treatment" and the filter for "controlled clinical trial" and "randomized clinical trial" as well as OVID medline (1946 to May week 2 2014) using the keyword ''ocular toxoplasmosis". The included studies were used to evaluate the various treatment modalities of TRC. Results. The electronic search yielded a total of 974 publications of which 44 reported on the treatment of ocular toxoplasmosis. There were 9 randomized controlled studies and an additional 3 comparative studies on the treatment of acute TRC with systemic or intravitreous antibiotics or on reducing the recurrences of TRC. Endpoints of studies included visual acuity improvement, inflammatory response, lesion size changes, recurrences of lesions, and adverse effects of medications. Conclusions. There was conflicting evidence as to the effectiveness of systemic antibiotics for TRC. There is no evidence to support that one antibiotic regimen is superior to another so choice needs to be informed by the safety profile. Intravitreous clindamycin with dexamethasone seems to be as effective as systemic treatments. There is currently level I evidence that intermittent trimethoprim-sulfamethoxazole prevents recurrence of the disease.

Repurposing the open access malaria box to discover potent inhibitors of Toxoplasma gondii and Entamoeba histolytica

Toxoplasmosis and amebiasis are important public health concerns worldwide. The drugs currently available to control these diseases have proven limitations. Therefore, innovative approaches should be adopted to identify and develop new leads from novel scaffolds exhibiting novel modes of action. In this paper, we describe results from the screening of compounds in the Medicines for Malaria Venture (MMV) open access Malaria Box in a search for new anti-Toxoplasma and anti-Entamoeba agents. Standard in vitro phenotypic screening procedures were adopted to assess their biological activities. Seven anti-Toxoplasma compounds with a 50% inhibitory concentration (IC50) of <5 μM and selectivity indexes (SI) of >6 were identified. The most interesting compound was MMV007791, a piperazine acetamide, which has an IC50 of 0.19 μM and a selectivity index of >157. Also, we identified two compounds, MMV666600 and MMV006861, with modest activities against Entamoeba histolytica, with IC50s of 10.66 μM and 15.58 μM, respectively. The anti-Toxoplasma compounds identified in this study belong to scaffold types different from those of currently used drugs, underscoring their novelty and potential as starting points for the development of new antitoxoplasmosis drugs with novel modes of action.

Development, characterizations and biocompatibility evaluations of intravitreal lipid implants

Background:

The treatment of posterior eye diseases is always challenging mainly due to inaccessibility of the region. Many drugs are currently delivered by repeated intraocular injections.

Objectives:

The purpose of this study was to investigate the potential applications of natural triglycerides as alternative carriers to synthetic polymers in terms of drug release profile and also biocompatibility for intraocular use.

Materials and Methods:

In vitro/in vivo evaluations of intravitreal implants fabricated from the physiological lipid, glyceride tripalmitate containing clindamycin phosphate as a model drug was performed. The micro-implants with average diameter of 0.4 mm were fabricated via a hot melt extrusion method. The extrudates were analyzed using scanning electron microscopy, differential scanning calorimetry, and in vitro drug dissolution studies. For biocompatibility, the implants were implanted into rabbit eyes. Clinical investigations including fundus observations, electroretinography as well as histological evaluations were performed.

Results:

In vitro tests guaranteed usefulness of the production method for preparing the homogenous mixture of the drug and lipid without affecting thermal and crystalinity characteristics of the components. In vitro releases indicated a bi-phasic pattern for lower lipid ratios, which were completed by the end of day three. With higher lipid ratios, more controlled release profiles were achieved until about ten days for a lipid ratio of 95%. Clinical observations did not show any abnormalities up to two months after implantation into the rabbit eye.

Conclusions:

These results suggest that although the implant could not adequately retard release of the present drug model yet, due to good physical characteristics and in vivo biocompatibility, it can represent a suitable device for loading wide ranges of therapeutics in treatment of many kinds of retinochoroidal disorders.

A typical bilateral Toxoplasma retinochoroiditis in a bone marrow transplant patient with negative serum titers

Background

Toxoplasma retinochoroiditis can have an atypical presentation and be difficult to diagnose in immunocompromised patients. Accurate diagnosis and appropriate treatment is important since the disease can be aggressive in these patients. This paper is a case report with literature review, emphasizing on the diagnosis and treatment of Toxoplasma retinochoroiditis.

Findings

A 27-year-old male with chronic myelogenous leukemia with history of bone marrow transplantation presented with floaters in his right eye. Fundus exam showed bilateral, multifocal retinochoroiditis with subsequent development of a mild vitritis. Serum cytomegalovirus and toxoplasmosis antibody titers and syphilis screen were negative. Aqueous polymerase chain reaction (PCR) analysis revealed the presence of Toxoplasma gondii DNA OU. Clindamycin (1.0 mg/0.1 mL) was injected bilateral intravitreal OU twice at 4 days apart with subsequent resolution of retinochoroiditis.

Conclusions

When evaluating retinochoroiditis in an immunocompromised patient, one must keep a high index of suspicion for atypical presentations of well-known disease entities. Aqueous and vitreous samples for PCR can be useful in obtaining an accurate diagnosis and therefore provide appropriate management for the patient. Intravitreal clindamycin is an option for treatment in these patients.

Successful treatment of toxoplasmosis-associated choroidal neovascular lesions with bevacizumab and antiparasitic therapy

PURPOSE

To report the effects of oral trimethoprim/sulfamethoxazole and intravitreal bevacizumab injection in the treatment of ocular toxoplasmosis-associated choroidal neovascular lesions (CNV).

METHODS

This was a noncomparative, nonrandomized, consecutive case series. All eyes with ocular toxoplasmosis-associated CNV received one intravitreal bevacizumab injection under the coverage of oral trimethoprim/sulfamethoxazole. The changes in best-corrected visual acuity were recorded. Serial fundus photography, fluorescein angiography, optical coherence tomography, and indocyanine green angiography were performed to measure the treatment efficacy.

RESULTS

Three eyes of two patients with a history of ocular toxoplasmosis had active CNV demonstrated by fluorescein angiography and optical coherence tomography. Each was treated with oral trimethoprim/sulfamethoxazole and one intravitreal bevacizumab injection. Best-corrected visual acuity, fundus photographs, fluorescein angiography, optical coherence tomography, and indocyanine green angiography all showed favorable results. No ocular or systemic complications were noted. In all three eyes, the CNV subsided and vision improved.

CONCLUSION

Oral trimethoprim/sulfamethoxazole is an effective and less expensive antibiotic against Toxoplasma gondii. Intravitreal bevacizumab injection appears to be a well-tolerated treatment for toxoplasmosis-associated CNV and has the potential as an adjuvant therapy to improve final vision. More cases and further studies are required.

Intravitreal clindamycin and dexamethasone for zone 1 toxoplasmic retinochoroiditis at twenty-four months

PURPOSE

To report the anatomic and functional outcomes of intravitreal clindamycin and dexamethasone for the treatment of zone 1 toxoplasmic retinochoroiditis (TRC). Patients had 1 or more of the following indications for local therapy: intolerance to oral medication, contraindication to oral medication because of pregnancy, lack of response despite oral antimicrobial treatment, or treatment with concomitant oral and local therapy to avoid or limit foveal or optic disc involvement.

DESIGN

Noncomparative, retrospective, multicentric interventional case series.

PARTICIPANTS

We reviewed the medical records of 12 consecutive patients (eyes) with posterior pole (zone 1) TRC who were treated weekly or every 4 weeks (during pregnancy) with intravitreal injections of clindamycin (1.5 mg/0.1 ml) and dexamethasone (400 microg/0.1 ml).

METHODS

Ophthalmic evaluation included Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity (BCVA); assessment of central macular thickness (CMT); resolution of inflammation by optical coherence tomography (OCT), clinical examination, and fluorescein angiography; and assessment of adverse events. Patients were followed for 24 months.

MAIN OUTCOME MEASURES

Resolution of TRC, changes in BCVA, and OCT.

RESULTS

Resolution of TRC was achieved in all cases with a mean number of injections of 3.6 (range: 2-5 injections) with a mean interval of 15.5+/-4 days. At 24 months a significant reduction in CMT by OCT was observed, from 387.6+/-70.1 microm to 185.2+/-44.7 microm (P = 0.0004). Baseline BCVA was logarithm of the minimal angle of resolution (logMAR) 1+/-0.4 (20/200), which improved to 0.5+/-0.4 (20/63) (P = 0.002) at the end of follow-up. Ten eyes (83.3%) improved > or =2 ETDRS lines of BCVA, and 2 eyes (20%) remained stable at 24 months. One patient's vision was limited because of macular scarring. No ocular or systemic adverse events were observed. No recurrences at 24 months of follow-up were observed.

CONCLUSIONS

The combination of intravitreal clindamycin and dexamethasone was associated with resolution of zone 1 TRC and functional and anatomic improvement in patients who did not tolerate, had contraindications to, or did not respond to oral medications.

Current approach in the diagnosis and management of posterior uveitis

Posterior uveitic entities are varied entities that are infective or non-infective in etiology. They can affect the adjacent structures such as the retina, vitreous, optic nerve head and retinal blood vessels. Thorough clinical evaluation gives a clue to the diagnosis while ancillary investigations and laboratory tests assist in confirming the diagnosis. Newer evolving techniques in the investigations and management have increased the diagnostic yield. In case of diagnostic dilemma, intraocular fluid evaluation for polymerase chain testing for the genome and antibody testing against the causative agent provide greater diagnostic ability.

Clinical features of ocular toxoplasmosis during pregnancy

PURPOSE

To evaluate the ocular characteristics of active ocular toxoplasmosis (OT) during pregnancy in nine female patients and to compare these attacks with those in the nonpregnant periods.

METHODS

Retrospective analysis of active OT during pregnancy and the nonpregnant periods. Outcome measurements consisted of the duration of attacks, the size of the retinal lesions, treatment strategies, and diverse ocular features and outcomes.

RESULTS

The 9 patients had 10 attacks during pregnancy and 24 attacks while not pregnant. One woman had recurrences during several pregnancies, and in total, three female patients had attacks only when pregnant. In general, the severity of the attacks during the pregnant and nonpregnant periods did not differ.

CONCLUSION

The attacks during pregnancy were not distinctively different in severity, duration, or outcome from the OT attacks outside pregnancy.