RGTA-based matrix therapy in severe experimental corneal lesions: safety and efficacy studies

Neurotrophic keratopathy: General features and new therapies

Neurotrophic keratopathy is an uncommon degenerative corneal disorder characterized by compromised corneal sensory innervation, resulting in the formation of epithelial defects and nonhealing corneal ulcers. Various treatment modalities are available to stabilize disease progression, improve patient well-being, and prevent vision loss. For eligible patients, medical and surgical reinnervation have emerged as pioneering therapies, holding promise for better management. This article presents a comprehensive review of the disease, providing an update relevant to ophthalmologists on pathogenesis, diagnosis, treatment options, and novel therapies targeting pathophysiological pathways.

First-Intention Incisional Wound Healing in Dogs and Cats: A Controlled Trial of Dermapliq and Manuka Honey

This study aimed to compare incisional wound healing in cats and dogs after the topical application of Μanuka honey and a new medical device, Dermapliq. Comparisons were made between each treatment and control, between the two treatments, and between dogs and cats. Twelve cats and twelve dogs were included in this study, and the impact of the two substances was examined through cosmetic, clinical, ultrasonographical, and histological evaluation. The use of Dermapliq in first-intention wound healing achieved a significantly better cosmetic evaluation score and better total clinical score at days 20-41, compared to the control, in both dogs and cats. The ultrasonographically estimated wound area was smaller with Dermapliq compared to the control. Wounds treated with Dermapliq showed histologically less inflammation compared to the control. The use of Manuka honey did not show a significantly better cosmetic score compared to the control. Skin thickening was significantly higher after using Manuka honey compared to the control and so was the total clinical score. However, the median wound area, as was evaluated ultrasonographically, was significantly smaller when wounds were treated with Manuka honey, the difference being more apparent in dogs. Dermapliq was proven to be a better choice in achieving favorable wound healing than Manuka honey in dogs and cats in first-intention healing. In our study, cats had a statistically better cosmetic score and less skin thickening and scar width compared to dogs. Histologically, cats showed significantly less edema, higher inflammation and angiogenesis scores, and lower fibroblast and epidermis thickening scores when compared to dogs.

Advanced platelet-rich fibrin promotes healing of induced corneal ulcer in donkeys (Equus asinus)

Ulcerative keratitis is a common disease in horses which may cause blindness. To prevent secondary bacterial and fungal infections and promote quick re-growth of the epithelial layer, different treatment approaches have been employed. This study aimed to examine the effects of advanced platelet-rich fibrin (A-PRF) gel on the healing process of experimentally induced corneal ulcers in donkeys. Nine healthy adult donkeys were used for the study. The donkeys were divided into two groups: the control group, where no medication was applied to the corneal ulcer, and the A-PRF gel group, where A-PRF gel was applied once a day on specific days after ulcer induction. The healing process was evaluated through various examinations and analyses. The results demonstrated that the A-PRF gel group showed significant improvement in the corneal ulcer area, with epithelial and stromal regeneration. At day 35, about 60% of the A-PRF group showed negative fluorescein uptake. Additionally, fewer complications were observed during the healing process compared to the control group. In conclusion, A-PRF gel is an important and safe therapeutic option for controlling ocular surface infection and promoting corneal healing. We recommend using A-PRF gel as an alternative approach, avoiding eyelid suturing, and minimizing corneal irritation.

Efficacy of Plasma Rich in Growth Factors (PRGF) in Stage 1 Neurotrophic Keratitis

Background/Aims

Neurotrophic keratitis (NK) is a neurodegenerative disease that can lead to corneal hypoesthesia, decreased tear production, and epitheliopathy. Based on the severity of ocular surface damage, NK is classified into 3 stages. Stage 1 NK is characterized by superficial punctate keratopathy, tear film instability, and reduced corneal sensation. The therapeutic efficacy of PRGF eye drops for NK stages 2 and 3 has been previously reported. In this study, we evaluated the efficacy and safety of autologous PRGF eye drops in improving corneal sensitivity and other ocular surface clinical signs in patients with stage 1 NK.

Methods

Retrospective chart review.

Results

26 eyes of 15 stage 1 NK patients (seven males, eight females), aged 76.3 ± 12.1 years, were included in the study. The mean treatment duration was 2 ± 1.8 months. With PRGF treatment, corneal sensitivity increased from 2.8 to 4.5 cm in 53.8% (14/26) (p < 0.01), TBUT increased from 3.6 to 5.0 s in 69.2% (18/26) (p < 0.01), and Schirmer score increased from 13.7 to 16.8 mm in 80.7% (21/26) of treated eyes (p < 0.01). Similarly, an improvement in corneal staining (punctate epithelial erosions) and MMP-9 levels was seen in 80.7% (n = 21) and 65.4% (n = 17) of treated eyes, respectively. BCVA improvement was seen in 26.9% of treated eyes (n = 7).

Conclusions

This study demonstrates the effective role of PRGF therapy in recovering corneal sensation and tear film function and in the healing of corneal erosions in stage 1 NK patients.

Treatment of Non-Infectious Corneal Injury: Review of Diagnostic Agents, Therapeutic Medications, and Future Targets

Corneal injuries can occur secondary to traumatic, chemical, inflammatory, metabolic, autoimmune, and iatrogenic causes. Ocular infection may frequently occur concurrent to corneal injury; however, antimicrobial agents are excluded from this present review. While practitioners may primarily rely on clinical examination techniques to assess these injuries, several pharmacological agents, such as fluorescein, lissamine green, and rose bengal, can be used to formulate a diagnosis and develop effective treatment strategies. Practitioners may choose from several analgesic medications to help with patient comfort without risking further injury or delaying ocular healing. Atropine, cyclopentolate, scopolamine, and homatropine are among the most frequently used medications for this purpose. Additional topical analgesic agents may be used judiciously to augment patient comfort to facilitate diagnosis. Steroidal anti-inflammatory agents are frequently used as part of the therapeutic regimen. A variety of commonly used agents, including prednisolone acetate, loteprednol, difluprednate, dexamethasone, fluorometholone, and methylprednisolone are discussed. While these medications are effective for controlling ocular inflammation, side effects, such as elevated intraocular pressure and cataract formation, must be monitored by clinicians. Non-steroidal medications, such as ketorolac, bromfenac, nepafenac, and diclofenac, are additionally used for their efficacy in controlling ocular inflammation without incurring side effects seen with steroids. However, these agents have their own respective side effects, warranting close monitoring by clinicians. Additionally, ophthalmologists routinely employ several agents in an off-label manner for supplementary control of inflammation and treatment of corneal injuries. Patients with corneal injuries not infrequently have significant ocular surface disease, either as a concurrent pathology or as an exacerbation of previously existing disease. Several agents used in the management of ocular surface disease have also been found to be useful as part of the therapeutic armamentarium for treatment of corneal injuries. For example, several antibiotics, such as doxycycline and macrolides, have been used for their anti-inflammatory effects on specific cytokines that are upregulated during acute injuries. There has been a recent wave of interest in amniotic membrane therapies (AMTs), including topical, cryopreserved and dehydrated variants. AMT is particularly effective in ocular injuries with violation of corneal surface integrity due to its ability to promote re-epithelialization of the corneal epithelium. Blood-based therapies, including autologous serum tears, plasma-enriched growth factor eyedrops and autologous blood drops, have additionally been explored in small case series for effectiveness in challenging and recalcitrant cases. Protection of the ocular surface is also a vital component in the treatment of corneal injuries. Temporary protective methods, such as bandage contact lenses and mechanical closure of the eyelids (tarsorrhaphy) can be particularly helpful in selective cases. Glue therapies, including biologic and non-biologic variants, can also be used in cases of severe injury and risk of corneal perforation. Finally, there are a variety of recently introduced and in-development agents that may be used as adjuvant therapies in challenging patient populations. Neurotrophic corneal disease may occur as a result of severe or chronic injury. In such cases, recombinant human nerve growth factor (cenegermin), topical insulin, and several other novel agents may be an alternate and effective option for clinicians to consider.

Comparative Analysis of Matrix-Regenerating Agent and Corneal Cross-Linking in an Experimental Alkali Burn Rabbit Model

PURPOSE

This study aimed to investigate the clinical and histopathological effects of corneal cross-linking (CXL) and matrix-regenerating agent (RGTA) treatments after corneal alkali burn.

MATERIALS AND METHODS

Twenty-four alkali-burned corneas from 24 rabbits were divided into three groups: control, CXL, and RGTA. All animals were investigated for epithelial healing, opacification, ulceration, and neovascularization at days 1, 7, 14, and 21 after the alkali burn. Corneas were excised and sent for histological examination on day 21.

RESULTS

One animal each from the CXL and control groups exhibited moderate ulceration, while no ulceration was observed in the RGTA group. No significant difference was observed among the groups in corneal thickness or corneal opacity measurements at the final visit (p = .058 and p = .544, respectively). Both RGTA and CXL treatments were effective in terms of epithelial healing and neovascularization (p = .023 and p = .03, respectively). On histological examination, the CXL and RGTA groups were more effective in treating epithelial loss, stromal edema, corneal vascularization, and leukocytic infiltration than the control group (p < .05). The immunohistochemical staining scores of the CXL and RGTA groups for caspase-3, vascular endothelial growth factor, and matrix metalloproteinase-9 in the epithelium and stroma were significantly lower than those in the control group (p < .05). In the immunohistochemical examination for inducible nitric oxide synthase, epithelial staining scores were similar among the groups (p > .05). In contrast, the stromal staining scores of the CXL and RGTA groups were lower than those of the control group (p < .05).

CONCLUSION

Both CXL and RGTA therapies were effective in reducing anatomical and histopathological complications after corneal alkali burn. Further investigation is needed to determine the optimal timing, duration, and dosage of these treatments.

Advances in the Medical Management of Neurotrophic Keratitis

Neurotrophic Keratitis (NK) is a degenerative disorder of the cornea characterized by decreased or absent sensory corneal innervation, corneal epitheliopathy and impaired healing.The clinical presentation of NK can range from persistent epithelial defects to corneal perforation and management is often both challenging and protracted. Historically, the management of NK has consisted of non-specific strategies to facilitate corneal epithelial healing such as lubrication, bandage contact lenses and tarsorrhaphy. Recent advances in the development of therapeutics for NK have provided new and efficacious targeted strategies for its management.In this article, we review recombinant human nerve growth factor (Cenegermin), currently approved for clinical use in the United States and Europe, as well as other promising therapeutic options that are in pre-clinical development such as thymosine β4, connexin43 inhibitors, and artificial extracellular matrix components.

ReGeneraTing Agents (rgta®) technology combined with antibiotics improves outcomes for infections in the upper limb

A matrix therapy agent marketed as CACIPLIQ20® showed marked improvement in the healing rate of hand infections, including functional recovery. It can be used at both earlier and later stages to promote faster healing and prevent an adverse outcome.

Matrix Regenerating Agent (RGTA) in a Neurotrophic Corneal Ulcer

Neurotrophic keratopathy is a condition associated with corneal damage and impaired corneal healing. There are no specific treatments available for this disease and current treatments are not associated with improved visual function. Matrix regenerating agents (RGTA) are recent topical agents showing positive results in the treatment of several corneal conditions, including neurotrophic keratopathy.

We report the case of a 73-year-old patient with a neurotrophic ulcer treated with RGTA.

Treatment with RGTA allowed complete corneal healing and a dramatic recovery in visual function in our patient. RGTA solutions are an important and safe therapeutic option for the treatment of selected corneal pathology.

Case Reports for Topical Treatment of Corneal Ulcers with a New Matrix Therapy Agent or RGTA® in Dogs

Superficial corneal ulcers that fail to heal within a normal time period and are refractory to conventional therapy in dogs are common in veterinary practice. Different etiologies can lead to this result, including spontaneous chronic corneal epithelial defects (SCCEDs) and ulcerative keratitis associated with bullous keratopathy. Thus, there is an urgent need to find new therapeutic approaches such as matrix therapy replacement. To determine the efficacy of a new ophthalmic treatment (Clerapliq^®) for SCCEDs and ulcerative keratitis associated with bullous keratopathy, a total of 11 dogs referred to the clinic because of nonhealing erosive ulcers after a classic primary treatment were enrolled to get this new treatment. Dogs underwent ophthalmic exams and 7 dogs (10 eyes) were diagnosed with superficial ulceration and 4 dogs (5 eyes) with bullous keratopathy due to endothelial dystrophy/degeneration. They received eye drops of Clerapliq^® every 3 days until recovery. The results showed that the corneas with recurrences of the ulcers were resolved predominantly by using Clerapliq^® every 3 days in 83.3% of the cases during a period of treatment ranging between 6 to 35 days. Therefore, this new approach using matrix therapy regenerating technology in treating superficial ulcers and bullous keratopathy in dogs can be successfully considered as an adjunctive therapy.

Recent innovations with drugs in clinical trials for neurotrophic keratitis and refractory corneal ulcers

Introduction: Corneal ulcers normally resolve spontaneously because of the proliferative ability of the corneal epithelium; however, sometimes, epithelial healing is diminished, even when standard treatments are administered. Hence, the treatment of refractory corneal ulcers is challenging and is the subject of ongoing efforts in preclinical and clinical development. Emerging treatment approaches include thymosine β4, CODA001, and topical insulin. Cenegermin eye drops, containing recombinant human nerve growth factor and ReGenerating Agent, a matrix therapy agent, have recently been commercialized for the treatment of moderate to severe neurotrophic keratitis in adults.Areas covered: We describe emerging therapeutic approaches for the management of refractory corneal ulcers and treatments recently introduced to the market. Pubmed and Clinicaltrial.gov databases were first searched including the terms: "corneal ulcer" or "neurotrophic keratopathy" and "treatment." Each treatment was searched in the same databases separately.Expert opinion: Affections of the sensory corneal nerves are the main factor contributing to the pathophysiology of neurotrophic keratopathy; this explains the healing difficulties of this form of ulcer. Cenegermin is a promising therapy acting as a neurotrophic agent for corneal healing. ReGenerating Agent has led to rapid pain relief and corneal healing, but randomized clinical trials are still necessary for further assessment.

Antiviral effects of Cacicol®, a heparan sulfate biomimetic for corneal regeneration therapy, for herpes simplex virus type-1 and varicella zoster virus infection

BACKGROUND

Cacicol^®, a topical eye biopolymer containing a poly-carboxymethylglucose sulfate solution that is a regenerating matrix therapy agent, intended for wound healing of persistent corneal epithelial defects. Based on the chemical composition, we hypothesized that Cacicol^® may compete with natural heparan sulfate (HS) which initiates cell surface attachment of herpes simplex virus type-1 (HSV-1), varicella zoster virus (VZV) and human adenovirus (HAdV), three viruses associated with corneal infections.

METHODS

Cacicol^® was compared to vehicle in the following viral strains: HSV-1 SC16 strain and HSV-1 PSLR, a clinical isolate highly resistant to acyclovir and foscarnet; VZV ATH and VZV FLO, two VZV clinical isolates; and HAdV-D37 strain. Viruses in Cacicol^® or vehicle were added to cells for 1 h during adsorption then viral replication was assessed by plaque reduction assays on Vero cells for HSV-1 and MeWo cells for VZV and by immunostaining assay on Hep-2 cells for HAdV-D37.

RESULTS

The vehicle had no effect, dose-dependent effects were demonstrated when HSV-1 SC16, HSV-1 PSLR, VZV ATH and VZV FLO were inoculated in the presence of Cacicol^®, inhibiting viral replication by 98.4%, 98.9%, 90.1% and 89.0%, respectively. Cacicol^® had no antiviral effect against HAdV-D37.

CONCLUSIONS

Cacicol^® has a significant antiviral activity on HSV-1 and VZV, but not on HAdV-D37. The lack of effect on HAdV is probably because it is less dependent on HS interactions for cell entry. Clinical studies are necessary to determine Cacicol^® for an adjunct or alternative therapy of corneal HSV-1 or VZV infection, particularly for the management of antiviral resistant HSV-1.

Treatment of spontaneous corneal perforation secondary to undiagnosed Sjögren's syndrome using regenerating agent and autologous serum eye drops

PURPOSE

The aim of this study was to report a case of sterile corneal ulcer leading to perforation, which was treated effectively with autologous serum eye drops, topical regenerative agent (poly-carboxymethylglucose sulfate), steroids, and systemic immunosuppression in a patient with undiagnosed primary Sjögren's syndrome.

METHODS

A 74-year-old female presented with a month's history of gradually worsening blurry vision in her left eye. Ophthalmic examination revealed a central descemetocele with excessive corneal stromal melting and absence of signs of infection. A bandage contact lens was applied for tectonic support along with topical corticosteroid and antibiotic drops. Autoimmune screen disclosed a diagnosis of Sjögren's syndrome, and the patient was commenced on systemic immunosuppression. Forty-eight hours after presentation, the patient developed a localized corneal perforation, presenting with a flat anterior chamber.

RESULTS

Urgent amniotic membrane transplantation was arranged while topical dexamethasone, moxifloxacin, and autologous serum eye drops were administered. After 24 h of intensive topical treatment, a significant reforming of the anterior chamber and subsequent gradual regeneration of the corneal stroma were noted, thus postponing amniotic grafting. The patient remained under close monitoring, showing progressive clinical improvement. Regenerating agent eye drops (Cacicol20^®) were also applied over the next month, with careful and slow tapering of topical dexamethasone. Further improvement of corneal thickness was observed, and visual acuity increased to 20/80.

CONCLUSION

This case report demonstrates the successful medical treatment of an autoimmune-related sterile corneal perforation without surgical intervention, highlighting the fact that early diagnosis and rigorous medical treatment with autologous serum and regenerating agent eye drops can effectively aid tissue regeneration and favorable visual rehabilitation.

ReGeneraTing Agents (RGTA®): A new option for healing and improving treatment outcomes for traumatic and burn injuries of the hand

CACIPLIQ20® significantly improved the outcomes of severe burn injuries of the hand. Healing was accelerated, with little or no scarring, allowing for greater mobility over the joints and maintained suppleness. Functional recovery was achieved in all cases.

Role of corneal nerves in ocular surface homeostasis and disease

Corneal nerves are key components of the physiological system that controls ocular surface homeostasis. The cornea is primarily innervated by the ophthalmic branch of the trigeminal nerves (cranial nerve V), which distend bilaterally from the pons. The nasociliary branch (afferent) of the ophthalmic nerve is sensory for cornea, eyelid and conjunctiva. These nerve fibres play a role in sensing temperature, chemical and mechanical stimuli, and pain, whereas, branches of the facial nerve (cranial nerve VII) contain motor nerves that control blinking and autonomic (sympathetic and a paucity of parasympathetic) fibres that stimulate tear production and secretion via feedback loops between the ocular surface, lacrimal glands and brain. Disruption of these nerves with interruption of neural feedback loops between the ocular surface and lacrimal glands can lead to corneal diseases such as dry eye disease (DED) and neurotrophic keratopathy (NK). Inversely, hypersensitivity of the nerve fibres and/or dysregulation of pain-controlling nervous centres may lead to neuropathic pain. Recently, medications that specifically target regeneration of corneal nerves have started to become available - and considering the high prevalence of diseases associated with corneal nerve dysfunction, these agents promise to fulfil a hitherto important unmet need. In this review, we explore the physiology of corneal nerves, the pathology of corneal nerve diseases and how these relate to neuropathic pain, NK and DED. We also discuss what novel treatments may be useful against diseases involving corneal nerves.

ReGeneraTing Agents (RGTA®) are a new option to improve amputation outcomes in the recovery of severe hand injuries

CACIPLIQ20® was used to accelerate the healing process and stimulate the viability of flaps and skin grafts, thereby improving amputation outcomes. An excellent range of motion was achieved with hardly any contracture or scarring. Pain relief and reduced sensitivity was noted, while healing of bone and tendon also improved, resulting in functional recovery.

Evaluation of corneal epithelial wound healing after penetrating keratoplasty in patients receiving a new matrix therapy agent (regenerating agent)

OBJECTIVES

Complete epithelial wound healing is a milestone in early postoperative care after penetrating keratoplasty. The re-epithelialization rate after penetrating keratoplasty was measured in patients receiving a new matrix therapy agent (regenerating agent, Cacicol^®) that mimics heparan sulphates.

METHODS

This was a prospective, open-label, uncontrolled, single-centre observational study. A total of 33 consecutive patients (33 eyes) who underwent an 8.25-mm diameter penetrating keratoplasty were treated with regenerating agent eye drops: one drop in the operating theatre immediately after graft, then on alternate days. Patients were divided into those at low risk (13 patients) and high risk (20 patients) of delayed wound healing, and follow-up was performed by digital slit lamp with fluorescein-dye testing repeated daily at a fixed time. Dye area was measured using ImageJ freeware. The main endpoint was epithelial healing after regenerating agent therapy.

RESULTS

The mean ± standard deviation time to complete healing for all patients was 2.7 ± 1.1 (median: 3, range: 1-6) days. This was obtained on Day 1 for 15% of patients, Day 2 for 33%, Day 3 for 88%, Day 4 for 94% and Day 6 for 100%. There was no significant difference between low- and high-risk patients. The area of epithelial defect decreased by a mean ± standard deviation of 75% ± 22% between Day 1 and Day 2, corresponding to a mean ± standard deviation wound-healing rate of 11.5 ± 6.5 mm²/D. There were no systemic or local side effects related to regenerating agent.

CONCLUSION

These preliminary data suggest that regenerating agent could be a useful, non-invasive therapeutic approach in postoperative management of penetrating keratoplasty with the potential to accelerate re-epithelialization.

Application of Novel Drugs for Corneal Cell Regeneration

Corneal transplantation has been the only treatment method for corneal blindness, which is the major cause of reversible blindness. However, despite the advancement of surgical techniques for corneal transplantation, demand for the surgery can never be met due to a global shortage of donor cornea. The development of bioengineering and pharmaceutical technology provided us with novel drugs and biomaterials that can be used for innovative treatment methods for corneal diseases. In this review, the authors will discuss the efficacy and safety of pharmacologic therapies, such as Rho-kinase (ROCK) inhibitors, blood-derived products, growth factors, and regenerating agent on corneal cell regeneration. The promising results of these agents suggest that these can be viable options for corneal reconstruction and visual rehabilitation.

A New Matrix Therapy Agent for Faster Corneal Healing and Less Ocular Discomfort Following Epi-off Accelerated Corneal Cross-linking in Progressive Keratoconus

PURPOSE

To investigate the hypothesis that a new matrix therapy agent (ReGeneraTing Agent, [RGTA]) would speed up the corneal reepithelialization, improve stromal healing, and reduce ocular symptoms after epi-off corneal cross-linking (CXL).

METHODS

Sixty eyes of 60 patients with progressive keratoconus were enrolled in the study. Epi-off accelerated CXL was performed in all patients. Sixty eyes were randomized into two groups according to use of RGTA eye drops prior to contact lens fitting at the end. Identical medical agents were started postoperatively for the two groups. All participants were monitored on 3 consecutive days after the CXL. Ocular pain, burning, stinging, tearing, photophobia, conjunctival hyperemia, and corneal healing status were evaluated.

RESULTS

By day 2, 25 eyes (83.3%) with RGTA revealed complete healing compared to 4 eyes (13.3%) that revealed complete healing in the control group (P < .001). All eyes had complete corneal epithelial defect closure by day 3 in both groups. Ocular pain scores were lower in the RGTA group on days 0, 1, and 2 (all P < .05). Burning scores were lower on days 1 and 2; stinging scores on days 2 and 3; tearing scores on days 2 and 3; and photophobia on days 1 and 2 (P < .05) in the RGTA group compared to the control group.

CONCLUSIONS

RGTA ophthalmic solution facilitates corneal healing by reconstructing the extracellular matrix in the wound area, leading to an earlier relief of symptoms for patients. [J Refract Surg. 2017;33(3):163-170.].

Evaluation of a new matrix regenerating agent in patients with Sjögren syndrome and superficial ulcerative keratitis resistant to conventional therapy: A report of 3 cases

RATIONALE

Sjögren syndrome (SS) is frequently associated with ulcerative keratitis, which is difficult to treat due to lacrimal tear deficiency and inflammation of the ocular surface.

PATIENT CONCERNS

We report the successful additive effect of a matrix regenerating agent (RGTA, Cacicol) in SS patients with severe superficial ulcerative keratitis resistant to conventional therapy.

DIAGNOSES

Retrospective, noncomparative case series of patients with primary or secondary SS associated with chronic diffuse keratitis.

INTERVENTIONS

All patients (3 women, aged 46, 59, and 84 years) had several years of dry-eye disease history and recurrent keratitis despite having used maximal dose topical therapies including artificial tear substitutes, topical vitamin A, and cyclosporine 0.05% emulsion. All patients suffered from dry, diffuse, and chronic superficial keratitis of at least 75% of the corneal surface, with no sign of corneal neovascularization or opacity.

OUTCOMES

RGTA treatment led to a rapid and marked decrease of ocular pain, burning, irritation, foreign body sensation, and improvement of visual acuity. Total diffuse keratitis healing occurred after several months of treatment. Discontinuation of RGTA administration led to the recurrence of severe keratitis; re-introduction of RGTA was successful. No local or systemic adverse effects related to treatment were reported.

LESSONS

RGTA treatment was effective and safe in this small series of 3 patients suffering from SS associated with recurrent or chronic superficial ulcerative keratitis resistant to conventional therapy.

Lack of effect of a topical regenerative agent on re-epithelialization rate of canine spontaneous chronic corneal epithelial defects: A randomized, double-masked, placebo-controlled study

Spontaneous chronic corneal epithelial defects (SCCEDs) are characteristic ulcers in dogs that are refractory to healing. The aim of the study was to evaluate the use of a topical regenerative agent to promote healing of SCCEDs. Nineteen dogs (20 eyes) were randomized to receive either regenerative agent (10 eyes) or placebo (10 eyes) every 48h following corneal debridement, which was repeated 1 week later if the SCCED had not yet healed. The mean±standard deviation time to re-epithelialization was 17.3±12.8 days for the group treated with a topical regenerative agent and 19.3±11.7 days for the group treated with a placebo; the cumulative healing rates were not statistically different (P>0.650). A positive association was found between the initial size of the ulcer and the time to re-epithelialization (r=0.555, P=0.011). Although well tolerated by dogs, there was no therapeutic advantage in using a topical regenerative agent for re-epithelialization of SCCEDs.

New Therapeutic Perceptions in a Patient with Complicated Herpes Simplex Virus 1 Keratitis: A Case Report and Review of the Literature

Patient: Male, 80

Final Diagnosis: Unilateral complicated Herpetic Simplex Virus 1 Keratitis

Symptoms: Visual impairment

Medication: Anti-herpetic treatment • Anti-VEGF • Cyclosporine A • Matrix regeneration therapy

Clinical Procedure: Amniotic membrane and limbal stem cell transplantation

Specialty: Ophthalmology

Polymeric nanocapsules: a potential new therapy for corneal wound healing

Corneal injuries are one of the most frequently observed ocular diseases, leading to permanent damage and impaired vision if they are not treated properly. In this sense, adequate wound healing after injury is critical for keeping the integrity and structure of the cornea. The goal of this work was to assess the potential of polymeric nanocapsules, either unloaded or loaded with cyclosporine A or vitamin A, alone or in combination with mitomycin C, for the treatment of corneal injuries induced by photorefractive keratectomy surgery. The biopolymers selected for the formation of the nanocapsules were polyarginine and protamine, which are known for their penetration enhancement effect. The results showed that, following topical instillation to a mouse model of corneal injury, all the nanocapsule formulations, either unloaded or loaded with cyclosporine A or vitamin A, were able to stimulate corneal wound healing. In addition, the healing rate observed for the combination of unloaded protamine nanocapsules with mitomycin C was comparable to the one observed for the positive control Cacicol®, a biopolymer known as a corneal wound healing enhancer. Regarding the corneal opacity, the initial grade of corneal haze (>3) induced by the photorefractive keratectomy was more rapidly reduced in the case of the positive control, Cacicol®, than in corneas treated with the nanocapsules. In conclusion, this work shows that drug-free arginine-rich (polyarginine, protamine) nanocapsules exhibit a positive behavior with regard to their potential use for corneal wound healing.

Matrix regenerative therapy

The extracellular matrix (ECM) is responsible for many of the cell behavior processes, including cell proliferation and growth, survival, change in cell shape, migration, and differentiation. The most important component of the ECM is heparan sulfate (HS), because it insures the storage of many cell communication proteins, necessary for the continuous and identical renewal of cells and thus for tissue regeneration. Regenerating agents (RGTA®) are bioengineered structural analogues of heparan sulfate glycosaminoglycans that replace the degraded endogenous HS of the ECM. In the ophthalmological field, RGTA® represents an innovative approach for the improvement of the ocular surface wound healing and matrix remodeling and plays a role in controlling and regulating the wound healing process in various ocular diseases.

RGTA® or ReGeneraTing Agents mimic heparan sulfate in regenerative medicine: from concept to curing patients

The importance of extracellular matrix (ECM) integrity in maintaining normal tissue function is highlighted by numerous pathologies and situations of acute and chronic injury associated with dysregulation or destruction of ECM components. Heparan sulfate (HS) is a key component of the ECM, where it fulfils important functions associated with tissue homeostasis. Its degradation following tissue injury disrupts this delicate equilibrium and may impair the wound healing process. ReGeneraTing Agents (RGTA^®s) are polysaccharides specifically designed to replace degraded HS in injured tissues. The unique properties of RGTA^® (resistance to degradation, binding and protection of ECM structural and signaling proteins, like HS) permit the reconstruction of the ECM, restoring both structural and biochemical functions to this essential substrate, and facilitating the processes of tissue repair and regeneration. Here, we review 25 years of research surrounding this HS mimic, supporting the mode of action, pre-clinical studies and therapeutic efficacy of RGTA^® in the clinic, and discuss the potential of RGTA^® in new branches of regenerative medicine.

Matrix Regeneration Therapy: A Case Series of Corneal Neurotrophic Ulcers

PURPOSE

Treating corneal neurotrophic ulcers is challenging. Topical application of matrix regeneration therapy (RGTA), which is a dextran derivative polymer and heparan sulfate analog, is a promising regenerative therapy and an alternative or additional therapeutic regimen when corneal healing is compromised. The aim of this study was to evaluate the efficacy of RGTA (Cacicol) in the treatment of 6 patients with severe neurotrophic ulcers.

METHODS

We present an uncontrolled prospective case series of 6 patients (6 eyes) with severe corneal neurotrophic ulcers. Patients were treated with topical RGTA at a dose of 1 drop every second day. The main outcome measure was complete corneal epithelialization. We measured corneal thickness by anterior segment swept-source optical coherence tomography.

RESULTS

Two patients (33%) showed complete corneal healing, one at 6 weeks and the other at 10 weeks. Treatment was considered failure in 4 patients (67%), and 1 patient had corneal perforation. None of the patients showed improvement in best-corrected visual acuity. There were no RGTA-related local or systemic side effects.

CONCLUSIONS

Based on previous studies, RGTA seems to be a promising therapeutic agent for controlling ocular surface inflammation and promoting corneal healing. In this study, the efficacy of RGTA did not match the encouraging results from previous reports.

RGTA in corneal wound healing after transepithelial laser ablation in a rabbit model: a randomized, blinded, placebo-controlled study

PURPOSE

To evaluate the efficacy of the agent RGTA for epithelial, stromal and nerve regeneration after laser-induced corneal wounding in rabbits.

METHODS

After excimer laser wounding of the anterior cornea in 25 New Zealand white rabbits, topical RGTA or placebo was applied in a randomized, masked manner. Fluorescein epithelial staining was performed on the first 5 postoperative days. In vivo confocal microscopy of corneal subbasal nerves and stroma was performed preoperatively and on week 2, 4, 8 and 16. At 16 weeks, corneas were stained for beta-III tubulin expression.

RESULTS

Postoperatively, all epithelia had closed by at least 90% after the third postoperative day. No significant difference in epithelial wound size was found between RGTA and placebo-treated groups, and RGTA did not hinder fluorescein binding. After epithelial wound closure, corneas remained transparent to 16 weeks. By confocal microscopy, subclinical stromal haze was significantly deeper in placebo-treated eyes (mean depth 60 μm) relative to RGTA group (52 μm), p = 0.02. Regenerating beta-III tubulin-positive subbasal nerves were observed in all corneas, but partial masking by haze rendered quantitative analysis unreliable.

CONCLUSIONS

RGTA restored stromal microarchitecture and reduced subclinical haze relative to placebo. The mild epithelial wound quickly healed regardless of treatment suggesting an optimal natural healing process in freshly wounded healthy corneas, and indicating that RGTA may be more suitable for healing of chronic or more aggressive wounds. Limitations of the rabbit model for nerve quantification in the presence of haze should also be recognized.

Assessment of therapeutic options for reducing alkali burn-induced corneal neovascularization and inflammation

This article aims to review and provide the current knowledge of the possibilities of topical treatment of corneal neovascularization due to alkali burns, evidenced by laboratory experiments, in vitro studies, and clinical trials published in the specialized literature. Authors present clinically relevant treatment of corneal neovascularization used in clinical practice, potential antiangiogenic topical therapeutics against corneal neovascularization, which are under investigation, and anti-angiogenic gene-therapy.

Effect of the Regenerative Agent Poly(Carboxymethylglucose Sulfate) on Corneal Wound Healing After Corneal Cross-Linking for Keratoconus

PURPOSE

To evaluate the effect of a regenerative agent (RGTA) [Cacicol20-poly(carboxymethyl glucose sulfate); OTR3, Paris, France] on corneal reepithelialization and pain after corneal cross-linking (CXL) for keratoconus.

METHODS

In this prospective comparative (contralateral) clinical study, patients with bilateral progressive keratoconus underwent CXL treatment. The corneal epithelium during CXL was removed using transepithelial phototherapeutic keratectomy (Cretan protocol). One eye of each patient was randomly instilled with an RGTA (Cacicol20) once a day (study group), whereas the fellow eye was instilled with artificial tears (control group). Patients were examined daily until complete reepithelialization. Postoperative examinations included slit-lamp biomicroscopy to assess the epithelial defect size and subjective evaluation of pain.

RESULTS

The study enrolled 18 patients (36 eyes). The mean epithelial defect size for study and control groups was 19.6 ± 4.2 mm versus 21.5 ± 2.8 mm, respectively, at day 1 (P = 0.019) and 6.4 ± 3.4 mm versus 7.9 ± 4.3 mm, respectively, at day 2 (P = 0.014). At day 3 postoperatively, 61.1% of study eyes were fully reepithelialized, compared with 11.1% of control eyes (P = 0.002).

CONCLUSIONS

RGTA (Cacicol20) instillation seems to result in faster corneal reepithelialization after CXL in this study. However, there was no significant effect in subjective pain/discomfort.

Treatment of Acanthamoeba neurotrophic corneal ulcer with topical matrix therapy

Background

This study was done to evaluate the visual and anatomical outcomes of topical regenerating agents as a novel therapy for neutrophic corneal ulcer (NCU) secondary to acanthamoeba infection.

Findings

A 20-year-old woman with a history of contact lens wear was referred to our hospital for keratitis after responding poorly to conventional treatment. In vivo confocal microscopy images suggested acanthamoeba keratitis with double-walled cysts in the anterior corneal stroma. Acanthamoeba infection was confirmed by laboratory findings. She was started on 0.1 % propamidine and 0.02 % chlorhexidine drops every hour. The antibiotic and antifungal drops were stopped when bacterial and fungal cultures proved negative. A central neurotrophic corneal ulcers (NCU) appeared, and despite treatment with artificial tears, bandage contact lens, and autologous serum, the ulcer worsened and she was treated with topical CACICOL20 (1 drop every 2 days) for 8 weeks. The corneal defect was completely repaired in 3 weeks. The treatment was well tolerated, and no local or systemic side effects were noted. Visual acuity remained 20/400. Two months later, the defect was still closed and the patient continued with 0.1 % propamidine and 0.02 % chlorhexidine drops, bandage contact lens, artificial tears, and autologous serum.

Conclusions

Topical regenerating agents interact with components of the extracellular matrix, binding matrix proteins and protecting them from proteolysis, restoring the matrix environment, and improving tissue healing. In this case, CALCICOL20 was effective for vision stabilization, wound healing, and was well tolerated for NCU secondary to acanthamoeba infection.

Oxidative stress to the cornea, changes in corneal optical properties, and advances in treatment of corneal oxidative injuries

Oxidative stress is involved in many ocular diseases and injuries. The imbalance between oxidants and antioxidants in favour of oxidants (oxidative stress) leads to the damage and may be highly involved in ocular aging processes. The anterior eye segment and mainly the cornea are directly exposed to noxae of external environment, such as air pollution, radiation, cigarette smoke, vapors or gases from household cleaning products, chemical burns from splashes of industrial chemicals, and danger from potential oxidative damage evoked by them. Oxidative stress may initiate or develop ocular injury resulting in decreased visual acuity or even vision loss. The role of oxidative stress in the pathogenesis of ocular diseases with particular attention to oxidative stress in the cornea and changes in corneal optical properties are discussed. Advances in the treatment of corneal oxidative injuries or diseases are shown.