Bovine Pericardium Membrane (Tutopatch) Combined With Solid Platelet-Rich Plasma for the Management of Perforated Corneal Ulcers

Bovine pericardium membrane (TutoPatch) for emergency repair of total corneal melting over an infected corneal graft

Purpose

Corneal perforation due to severe melting is a very dangerous, sight-threatening condition requiring immediate management due to the high risk of endophthalmitis and critical hypotony. In the case of perforated corneal grafts, retransplantation is usually postponed to avoid the detrimental effects of inflammation on the new graft. We describe the first case of the use of a TutoPatch graft for emergency replacement of a lamellar graft perforation over acute infectious total melting.

Observations

A 42-year-old male patient presented to the Emergency Department with pain in the left eye, which was red photophobic. He had been treated with bilateral deep anterior lamellar keratoplasty (DALK) for advanced keratoconus 5 years previously and had been experiencing recurrent corneal ulcers in the left eye within the last 8 months. Clinical examination documented corneal perforation over acute infectious melting involving the total graft surface in the left eye. The infected graft was removed along with the perforated infected residual Descemet membrane, and a double-layer TutoPatch covering was sutured to the host's margin with 10.0 nylon. The covering was left in place for three weeks, allowing the patient to undergo retransplant three weeks later without complications.

Conclusions and importance

TutoPatch covering can be safely used as an easy-to-preserve emergency material for a temporary bridge to retransplantation in large acute infectious corneal melting.

Advances and prospects of platelet-rich plasma therapy in veterinary ophthalmology

In the recent decades, there has been a significant uptick on the use of platelet-rich plasma (PRP) as a better alternative for ophthalmologic therapies in pathologies, primarily of the ocular surface. PRP is a class of liquid platelet concentrate containing a supra-physiological concentration of platelets in a relatively small amount of plasma. Its potential to heal various tissues has piqued interest in its therapeutic application as a biomaterial in regenerative medicine. It is currently a popular therapeutic agent in plastic surgery, cardiothoracic surgery, reconstructive surgery, and even oral and maxillofacial surgery. Based on the data from in vitro and in vivo studies, it can be concluded that PRP possesses adequate therapeutic potential in ocular pathologies, especially those involving cornea. In addition, the high concentrations of growth factors (TGF-β, VEGF, EGF) present in the PRP accelerate the healing of the corneal epithelium. PRP has great therapeutic prospects in veterinary ophthalmology as a regenerative therapeutic modality. However, several variables are yet to be defined and standardized that can directly affect the efficacy of PRP application in different ophthalmic conditions. There is a shortage of research on the use of PRP in ocular surface defects compared to the number of studies and reports on the use of autologous and allogeneic serum eye drops. Therefore, a data-driven approach is required to generate consensus/guidelines for the preparation, characterization, and therapeutic use of PRP in veterinary ophthalmology. This review aims to inform readers of the latest research on PRP, including its preparation methods, physiological and biochemical properties, clinical applications in veterinary ophthalmology, and their safety and efficacy.

Thymosin beta 4: A potential novel adjunct treatment for bacterial keratitis

Microbial keratitis is a rapidly progressing, visually debilitating infection of the cornea that can lead to corneal scarring, endophthalmitis, and perforation. Corneal opacification or scarring, a complication of keratitis, is among the leading causes of legal blindness worldwide, second to cataracts.Pseudomonas aeruginosaandStaphylococcus aureusare the two bacteria most commonly associated with this type of infection. Risk factors include patients who are immunocompromised, those who have undergone refractive corneal surgery, and those with prior penetrating keratoplasty, as well as extended wear contact lens users. Current treatment of microbial keratitis primarily addresses the pathogen using antibiotics. Bacterial clearance is of utmost importance yet does not guarantee good visual outcome. Clinicians are often left to rely upon the eye's innate ability to heal itself, as there are limited options beyond antibiotics and corticosteroids for treating patients with corneal infection. Beyond antibiotics, agents in use, such as lubricating ointments, artificial tears, and anti-inflammatory drops, do not fully accommodate clinical needs and have many potential harmful complications. To this end, treatments are needed that both regulate the inflammatory response and promote corneal wound healing to resolve visual disturbances and improve quality of life. Thymosin beta 4 is a small, naturally occurring 43-amino-acid protein that promotes wound healing and reduces corneal inflammation and is currently in Phase 3 human clinical trials for dry eye disease. Our previous work has shown that topical Tβ4 as an adjunct to ciprofloxacin treatment reduces inflammatory mediators and inflammatory cell infiltrates (neutrophils/PMN and macrophages) while enhancing bacterial killing and wound healing pathway activation in an experimental model ofP. aeruginosa-induced keratitis. Adjunctive thymosin beta 4 treatment holds novel therapeutic potential to regulate and, optimally, resolve disease pathogenesis in the cornea and perhaps other infectious and immune-based inflammatory disease. We plan to establish the importance of thymosin beta 4 as a therapeutic agent in conjunction with antibiotics with high impact for immediate clinical development.

Allogeneic Solid Platelet-Rich Plasma for Persistent Epithelial Neurotrophic Defects: A Protocol and Pilot Study

PURPOSE

Here, we present the procedure to obtain allogeneic solid platelet-rich plasma (PRP) and its use in a pilot study of patients with persistent neurotrophic epithelial defects.

METHODS

We included 4 eyes of 4 patients with persistent neurotrophic epithelial defects unresponsive to other therapies from a single institution. PRP and thrombin were produced by the Department of Transfusion Medicine from healthy blood donors. PRP was activated in its solid form in the operating room with addition of thrombin and calcium gluconate 10% and applied on the cornea with fibrin glue and soft contact lens. Corneal healing time, corneal esthesiometry, visual acuity, Oxford staining score, Ocular Surface Disease Index questionnaire, and Schirmer I test were recorded. Anterior segment optical coherence tomography and in vivo confocal microscopy were also evaluated over the 4-month follow-up period.

RESULTS

The persistent epithelial defect healed in all patients in the first 10 days. During the follow-up, there was an absence of recurrences. For all patients, there was a reduction in Ocular Surface Disease Index questionnaire score (case 1: -55 points, -73.3%; case 2: -26.3 points, -58.4%; case 3: -56 points, -69.1%; case 4: -20 points, -26.6%; mean reduction: 39.3 points, 56.85%) and Oxford staining score (case 1, 2, and 3: 3 points decrease; case 4: 2 points decrease; mean reduction: -2.75 points).

CONCLUSIONS

Allogeneic solid PRP in combination with fibrin glue may facilitate wound healing in neurotrophic persistent epithelial defects. Further prospective studies are needed to quantify its efficacy.

Initial Healing Effects of Platelet-Rich Plasma (PRP) Gel and Platelet-Rich Fibrin (PRF) in the Deep Corneal Wound in Rabbits

Platelet concentrates (PCs), including platelet-rich plasma (PRP) gel and platelet-rich fibrin (PRF), are autologous blood-derived biomaterials containing numerous growth factors. This study aimed to evaluate the initial healing effects of PRP gel and PRF on deep corneal wounds. Thirty-three eyes from New Zealand white rabbits were divided into four groups: group 1, lamellar keratectomy (LK); group 2, LK + commercial porcine small intestinal submucosal membrane (SIS); group 3, LK + SIS + PRP gel; and group 4, LK + SIS + PRF. Postoperative clinical and histological findings were observed for eight weeks. Group 1 showed no neovascularization during the observation period, and incompletely recovered with a thin cornea. Group 2 showed active healing through neovascularization, and a thick cornea was regenerated through the sufficient generation of myofibroblasts. Although group 3 showed a healing effect similar to that of group 2, angiogenesis and subsequent vessel regression were promoted, and corneal opacity improved more rapidly. In group 4, angiogenesis was promoted during initial healing; however, the incidence of complications, such as inflammation, was high, and myofibroblasts were hardly generated in the corneal stroma, which adversely affected remodeling. In conclusion, while PRP gel is a safe surgical material for promoting remodeling through vascular healing and myofibroblast production in deep corneal wounds, the use of PRF is not recommended.

Autologous Platelet‐Rich Plasma Drops for Evaporative Dry Eye Disease from Meibomian Gland Dysfunction: A Pilot Study

Purpose

To evaluate the effects of autologous platelet‐rich plasma (PRP) drops for evaporative dry eye (EDE) disease from meibomian gland dysfunction (MGD).

Methods

This is a retrospective, consecutive case series of 20 eyes of 10 patients with EDE from MGD treated with PRP drops from November 2020 to November 2021 at a single outpatient clinic in Ontario, Canada. PRP drops were prepared from whole blood using a two-step centrifugation method. Patients were instructed to instill these drops six times daily for 4 weeks. The Canadian Dry Eye Assessment (CDEA) questionnaire score, patient subjective assessment (PSA) score, first and average non-invasive break-up times (f/a NIBUT), tear meniscus height (TMH), bulbar redness (BR), and meibograph grade (MG) were measured before and after the treatment course.

Results

Significant improvements in dry eye symptoms and tear film parameters were observed. Dry eye symptoms significantly improved as per the CDEA (mean difference (MD) = −5.45, 95% confidence interval (CI) = [−7.9, −3.1], p<0.001) and PSA (MD = −2.6, 95% CI = [−3.9, −1.2], p<0.001). There were significant improvements in tear film parameters including fNIBUT (MD = 3.85s, 95% CI = [1.2, 6.8], p=0.006), aNIBUT (MD = −6.81s, 95% CI = [5.7, 11.1], p<0.001) and TMH (MD = 0.08, 95% CI = [0.003, 0.2], p=0.045). There was an improvement in conjunctival injection as measured by BR (MD = −0.36, 95% CI = [−0.4, −0.15], p=0.373). Five eyes experienced a one-grade improvement in MG (p=0.453), and none experienced worsening in MG with treatment. No temporary or permanent adverse effects were noted.

Conclusion

Four weeks of PRP therapy resulted in significant functional improvements in dry eye symptoms and tear film quality and quantity. Improvements in conjunctival injection and microstructural improvements in meibomian glands were also observed in some eyes. Overall, PRP is a promising treatment option for patients with EDE from MGD refractory to conventional treatments.

Cell and Cell Free Therapies in Osteoarthritis

Osteoarthritis (OA) is the most common articular disease in adults and has a current prevalence of 12% in the population over 65 years old. This chronic disease causes damage to articular cartilage and synovial joints, causing pain and leading to a negative impact on patients' function, decreasing quality of life. There are many limitations regarding OA conventional therapies-pharmacological therapy can cause gastrointestinal, renal, and cardiac adverse effects, and some of them could even be a threat to life. On the other hand, surgical options, such as microfracture, have been used for the last 20 years, but hyaline cartilage has a limited regeneration capacity. In recent years, the interest in new therapies, such as cell-based and cell-free therapies, has been considerably increasing. The purpose of this review is to describe and compare bioregenerative therapies' efficacy for OA, with particular emphasis on the use of mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP). In OA, these therapies might be an alternative and less invasive treatment than surgery, and a more effective option than conventional therapies.

Combined Platelet Rich Plasma and Amniotic membrane in the treatment of Perforated Corneal Ulcers

PURPOSE

To report the outcomes of using synthetic amniotic membrane with platelet rich plasma for the primary management of corneal perforations.

SETTING

Ophthalmology department. Faculty of Medicine, Minia University, Minia, Egypt.

METHODS

A case series of 10 patients diagnosed with corneal perforation underwent emergency surgical procedure for repair of the perforation through the implantation of synthetic amniotic membrane with platelet-rich plasma clot under it and the application of platelet-rich plasma eye drops, with a follow up period of up to 4 weeks.

RESULTS

All cases demonstrated formation of adequate intraocular pressure digitally, within the first 7 days, and all cases showed complete sealing of the corneal perforation within the 4 weeks follow up period, mild symptoms were reported only in the 1^st postoperative week like foreign body sensation and lacrimation. 3 of the treated patients underwent penetrating keratoplasty after 6 months with satisfactory visual outcomes.

CONCLUSION

The combination of amniotic membrane implant and platelet rich plasma in both the clot and eye drop forms is an effective and easy accessible method for the primary management of corneal perforations.

A comparison between dehydrated and cryopreserved heterologous corneal grafts for penetrating keratoplasty in dogs and cats

OBJECTIVE

To compare the efficacy of dehydrated and cryopreserved heterologous corneal grafts in the management of full-thickness corneal defects in cats and dogs.

ANIMALS STUDIED

Sixty-five cats (81 eyes) and 42 dogs (51 eyes) with full-thickness corneal defects of different origin.

MATERIALS AND METHODS

This prospective randomized trial included 132 animal eyes (81 feline and 51 canine) with different full-thickness corneal defects. Penetrating keratoplasty with cryopreserved and dehydrated corneal grafts was performed in 57 and 75 eyes, respectively. Follow-up lasted for 6 months.

RESULTS

Optically clear cornea with mild scarring was achieved in 40.4% of cases (23/57 eyes) after cryopreserved and in 42.7% of cases (32/75 eyes) after dehydrated corneal grafting. Moderate scarring after cryopreserved and dehydrated corneal grafting was observed in 35.1% of cases (20/57 eyes) and 37.3% of cases (28/75 eyes), respectively. Severe scarring and corneal opacities with severe vision loss after cryopreserved and dehydrated corneal grafting developed in 22.8% of cases (13/57 eyes) and 18.7% of cases (14/75 eyes), respectively. In two groups of animals combined, the affected eyes were salvaged and visual function improvement of varying degree was achieved in 78.0% of cases (103/132 eyes). Transplant rejection warranted enucleation in 1.75% of cases (1/57 eyes) and 1.3% of cases (1/75 eyes) after cryopreserved and dehydrated corneal grafting, respectively.

CONCLUSIONS

No statistically significant differences in clinical outcomes of penetrating keratoplasty with cryopreserved and dehydrated corneal grafts were observed. Dehydrated cornea may be considered a viable alternative to cryopreserved grafts for the management of full-thickness corneal defects.

Development of a Platelet Lysate-Based Printable, Transparent Biomaterial With Regenerative Potential for Epithelial Corneal Injuries

Purpose

To develop a human platelet lysate (hPL)–based bioink that is transparent and also encompasses the regenerative properties of hPL to facilitate wound healing.

Methods

The effect of different batches of hPLand fetal bovine serum (FBS) on corneal epithelial cell growth and scratch assay was first examined using Incucyte Zoom. Various combinations of human fibrinogen (concentration range from 0.2 to 5 mg/mL) and thrombin (concentration from 1 to 10 U/mL) were combined with hPL to generate nine types of potential bioink. Rheology, transparency, and cell compatibility of bioinks were assessed and compared. The final selected bioink was used in an ex vivo corneal model to examine its ability in re-epithelization.

Results

No significant difference was detected in cell proliferation and wound healing tests between different hPL batches at the same concentration. Scratch assay data showed that hPL had significantly higher effect on wound healing than FBS. Comparing across the nine bioinks, bioink 5 consisting of 10% hPL, 2 mg/mL fibrinogen, and 5 U/mL thrombin demonstrated all required mechanical and cellular properties and was able to regenerate the full-thickness epithelium ex vivo.

Conclusions

The results showed that a transparent and adhesive bioink can be generated by combining hPL, fibrinogen, and thrombin together. The bioink can be directly applied to a human cornea to promote corneal re-epithelization with huge potential applications in corneal injuries.

Translational Relevance

The developed transparent hPL-based ink with its adhesive and healing ability showed that it could be used as a new treatment option for corneal injuries.

Human Platelets and Derived Products in Treating Ocular Surface Diseases - A Systematic Review

Human platelet products have emerged as an alternative treatment for a range of ocular surface diseases such as dry eye and corneal ulceration. With significant therapeutic potential and increasing popularity, this study aimed to conduct a systematic review to detail the various production methods involved in generating platelet-derived products, compare and analyze clinical findings across available studies, and disseminate the relative advantages, limitations, and challenges of using platelet products to treat ocular surface disease. Thirty-eight clinical studies were identified, excluding studies conducted in animals and non-English language. Studies reported clinical outcomes, which included ocular surface disease index, best-corrected visual acuity, and corneal fluorescein staining. Most clinical studies reported improved patient signs and symptoms with an increasing variety of human platelet products including platelet rich plasma eye drops, human platelet lysate and platelet gels. However, due to variations in production methods, and study designs as well as confusing terminology, it was suggested that characterization of platelet products is needed for proper evaluation across studies.

Tendon elongation with bovine pericardium in strabismus surgery-indications beyond Graves' orbitopathy

BACKGROUND

For some patients with complex ocular motility disorders, conventional strabismus surgery is insufficient. Surgery with tendon elongation allows correction of larger angles and maintains a sufficient arc of contact for rectus muscles. This study reports results for tendon elongation with bovine pericardium (Tutopatch®) in indications other than Graves' orbitopathy in which it is already widely used.

METHODS

We reviewed the records of all patients who underwent surgery with Tutopatch® in our institution. Angles of squint and head postures were analyzed preoperatively, on the first postoperative day, and in the long term (median 9 weeks after the operation). Patients with Graves' orbitopathy were excluded.

RESULTS

From 2011 to 2018, the procedures on 58 eyes of 54 patients (35 females, median age 35 years (3-75)) met the inclusion criteria. Horizontal rectus muscle surgery (53 eyes) was conducted on patients with residual strabismus (13), Duane's retraction syndrome with eso- (type I: 16)/exodeviation (type II: 2, type III: 1), 6th (7)/3rd nerve palsy (7), Möbius syndrome (2), congenital fibrosis of the extraocular muscles type 3A (CFEOM3A, TUBB3 mutation) (4), and orbital apex syndrome (1). Vertical rectus muscle surgery (5 eyes) was conducted on patients with myasthenia (1), vertical tropia after orbital floor fracture (1), CFEOM1 (2), and Parry-Romberg syndrome (1). 42 eyes had prior eye muscle surgery (1-5 procedures, median 1). Out of 45 patients with postoperative long-term data, 43 showed an angle reduction. Fifty-one percent had an angle of 10Δ (prism diopter) or less, one had a significant over-effect, and 10 had revision surgery. For the heterogeneous group of residual eso- and exotropias, the median absolute horizontal angle was reduced from 35Δ (16 to 45Δ) to 9Δ (0 to 40Δ), for Duane's retraction syndrome from 27.5Δ (9 to 40Δ) to 7Δ (0 to 40Δ), and for sixth and third nerve palsies from 43Δ (20 to 75Δ) to 18Δ (4 to 40Δ). For 3 patients with vertical rectus muscle surgery, the median absolute vertical angle was reduced from 30Δ (20 to 45Δ) to 4Δ (1 to 22Δ). The motility range was shifted in the direction contrary to the elongated muscle in all subgroups. A considerable reduction of the excursion into the field of action of the elongated muscle had to be registered.

CONCLUSIONS

Strabismus surgery with bovine pericardium introduces new surgical options for complicated revisions and for rare and complex oculomotor dysfunctions. Yet, it has to be recognized that this type of surgery aiming at maximum effects, despite preservation or restitution of the arc of contact, leads to reduction of the excursion into the field of action of the elongated muscle. Furthermore, dose finding can be difficult depending on the underlying pathology and more than one intervention might be necessary for optimal results.

Quantification of Growth Factors and Fibronectin in Diverse Preparations of Platelet-Rich Plasma for the Treatment of Ocular Surface Disorders (E-PRP)

Purpose

The purpose of this study was to quantify the presence of growth factors (GFs) and fibronectin in autologous platelet-rich plasma for topical ocular use (E-PRP) comparing their concentration when different preparation and preservation procedures were applied.

Methods

E-PRP was prepared with blood from healthy volunteers. The count of platelets, leukocytes, and red blood cells in the whole blood and E-PRP were performed. The concentration of the GFs platelet-derived growth factor BB (PDGF-BB), transforming growth factor β1 (TGF-β1), epidermal growth factor (EGF), vascular endothelial growth factor A (VEGF-A), and fibronectin was determined in each of the four procedures applied including fresh, frozen at −20°C for 3 months, fresh-spin, and frozen-spin at −20°C E-PRP samples. Posterior statistical analysis was performed to establish significant differences between groups and between GFs in relation to the amounts of platelets.

Results

Platelets in the E-PRP doubled in the number of basal values of whole blood (P ≤ 0.01). The blood cells in the E-PRP decreased drastically in red cells (99%) and also in leukocytes (82%). The concentration of PDGF-BB and EGF was significantly higher (P < 0.01) when the E-PRP samples were frozen at −20°C. However, no significant differences were observed for TGF-β1, VEGF-A, and fibronectin (P > 0.05). The concentration of GFs in the E-PRP did not necessarily correlate with the number of platelets.

Conclusions

Freezing the E-PRP for 3 months at −20°C increased the concentration of important proteins, such as PDGF-BB and EGF, and maintained the levels of others. These findings are essential because treatments, such as E-PRP, used by patients with ocular surface dysfunctions tend to prolong it in time. In addition, subsequent centrifugation of the E-PRP decreased the values of TFG-β1, but not the other GFs, which would allow adjusting the concentration of TFG-β1, as necessary. This procedure guarantees their correct conservation and viability.

Translational Relevance

This work demonstrates how clinical application can be improved by starting from basic research. The quantification of GFs and fibronectin in platelet-rich plasma (PRP) helps to clarify which is the best mode of preparation and preservation of PRP for clinical applications. This allows to optimize the product that is delivered to the patients as a treatment for the dysfunctions of the ocular surface, guaranteeing that the conservation does not affect at all the quality of the PRP that it is going to be used.

Efficacy and safety of treatment of hyposecretory dry eye with platelet-rich plasma

OBJECTIVE

To evaluate and compare the symptomatology and clinical findings in hyposecretory dry eye of the treatment with platelet-rich plasma (PRP) and artificial tears of sodium hyaluronate (SH).

METHODS

Blind single-centre prospective comparative randomized study including 83 patients with hyposecretory dry eye and mean age of 64.0 years. Two groups were differentiated depending on the treatment applied: 44 patients treated with PRP (PRP group), and 39 patients treated with artificial tears of SH (SH group). Changes in Schimer test, tear osmolarity, corneal and conjunctival staining, tear film break-up time (TF-BUT), conjunctival hyperaemia, dry eye-related symptoms with the Ocular Surface Disease Index questionnaire, and caliciform cell density were evaluated during 30 days of treatment.

RESULTS

Significantly larger reduction in symptomatology (p < 0.001), visual improvement (p < 0.001), reduction in hyperaemia (p < 0.001), and corneal and conjunctival staining (p < 0.001), increment of Schirmer test outcome (p ≤ 0.005), and reduction of osmolarity were found in the PRP group in both eyes compared to SH group at 15 and 30 days of treatment. Likewise, a significantly higher increment of caliciform cell density (p < 0.001) was found in the PRP group. Strong and statistically significant correlations were found in the PRP group of the change achieved in visual acuity, hyperaemia, osmolarity, and conjunctival and corneal staining with the baseline values of these variables (p < 0.001).

CONCLUSION

PRP treatment in hyposecretory dry eye induces a more significant positive effect over symptomatology and different dry eye signs than SH, especially in moderate and severe cases.

The healing effect of the collagen-glycosaminoglycan copolymer on corneal thinning

Background

To study the healing processes of partial thickness wounds in the adult rabbit cornea after grafting a porous collagen-glycosaminoglycan copolymer matrix (CG).

Methods

In this study, the regeneration of surgically-induced rabbit corneal defect implanted with CG was investigated. The corneal partial thickness wound was created by 7.5 mm trephine. The wound was implanted with CG. Effects on wound healing was analyzed using clinical data on epithelial migration and corneal thickness, and histological data on collagen and alpha smooth muscle actin distribution.

Results

Compared with control group, CG induced a relatively severe inflammatory reaction in grafted cornea until the CG matrix was completely degraded. The new vessel ingrowth and stromal regeneration maintained the corneal thickness. The grafted cornea was significantly thicker (P < 0.001) than the control group. On day 90, the corneal opacity score of the control group was one and the grafted cornea was two.

Conclusion

CG copolymer matrix can successfully repair the damaged corneal stroma by injury, and regain its thickness. However, CG matrix induced inflammatory healing process thus causing mild corneal haziness and neovascularization.

Clinical trial of adjunctive autologous platelet-rich plasma treatment following diamond-burr debridement for spontaneous chronic corneal epithelial defects in dogs

OBJECTIVE To evaluate the effects of adjunctive treatment with autologous platelet-rich plasma (PRP) on corneal reepithelialization, vascularization, and fibrosis in dogs with spontaneous chronic corneal epithelial defects (SCCEDs). DESIGN Randomized, controlled, double-masked clinical trial. ANIMALS 40 client-owned dogs with uncomplicated SCCEDs. PROCEDURES All dogs were treated with diamond-burr epithelial debridement (DBD) of affected eyes, topical tobramycin solution and atropine sulfate ointment application, and Elizabethan collar placement for 4 weeks. Dogs were randomly assigned to topical ocular administration of autologous PRP (n = 20) or artificial tear solution (control group; 20) 4 times daily for 28 days. Recheck examinations were performed approximately 2 and 4 weeks after treatment began to evaluate SCCEDs for corneal reepithelialization, and semiquantitative corneal vascularization and corneal fibrosis scores were assigned according to affected corneal surface area. Results were compared between groups. RESULTS All dogs completed the study. The SCCEDs had completely reepithelialized in 11 (55%) control dogs and 12 (60%) PRP-treated dogs by the 2-week reevaluation, and in 15 (75%) control dogs and 18 (90%) PRP-treated dogs by the 4-week reevaluation. No significant differences were identified between groups in these proportions nor in mean differences from pretreatment scores for corneal vascularization and fibrosis. CONCLUSIONS AND CLINICAL RELEVANCE In this preliminary study involving dogs with uncomplicated SCCEDs, topical PRP administered as an adjunctive treatment following DBD had no significant effect on healing. A larger study is warranted to support or refute these findings and to determine the effects of adjunctive PRP treatment for dogs with complicated SCCEDs.

Clinical Efficacy of Platelet-Rich Plasma in the Treatment of Neurotrophic Corneal Ulcer

Purpose

Platelet-rich plasma (PRP) is an autologous blood product without preservatives and rich in proteins and growth factors which make it possible for cells to differentiate, proliferate, and migrate, thus stimulating healing and regeneration of tissues. The aim of this study was to evaluate the efficiency of autologous platelet-rich plasma in the treatment of neurotrophic keratopathy.

Methods

The study group consists of 25 patients with nonhealing corneal ulcers due to herpes simplex or herpes zoster infection and facial nerve or trigeminal nerve paralysis as a result of a neurosurgical operation caused by a tumour or stroke. The patients were given autologous platelet-rich plasma drops five times a day and additionally preservative-free artificial tears and a vitamin A ointment at night for maximum 3 months. The following were evaluated: best corrected visual acuity (BCVA), healing of corneal surface, subjective symptoms, and changes in corneal thickness with the use of anterior segment optical coherent tomography (AS-OCT).

Results

BCVA before the treatment was 0.10 ± 0.14, and after the treatment it was –0.3 ± 0.27 (p=0.001). Improved visual acuity and less subjective symptoms were observed in all patients. Complete healing of the ulceration was observed in 20 patients (80%). Four patients (16%) experienced considerable improvement of their clinical condition (reduced size and depth of the ulceration and inflammatory state: smaller conjunctival injection and swelling, improved visual acuity, and less subjective symptoms). In one of the patients, an amniotic membrane was transplanted due to the lack of improvement of his local condition. In all patients, the progression of corneal thinning was stopped. An average corneal thickness in its thinnest point was 322.3 ± 125.8 µm before the treatment, and 404.5 ± 118.7 µm (p < 0.05) after the treatment. None of the patients reported general or local side effects of the treatment.

Conclusions

Autologous platelet-rich plasma is a blood-based product which seems efficient in the treatment of neurotrophic keratopathy.

Platelet rich plasma for the management of hair loss: Better alone or in combination?

Platelet-rich plasma (PRP) and autologous protein-based treatments have recently emerged as a potential therapeutic approach for hair loss-related disorders including androgenetic alopecia and alopecia areata. The safety and efficacy of repeated intradermal injections of PRP has proved to promote hair growth in a number of randomized clinical trials. Biologically active proteins and cytokines released upon platelet activation have shown to induce folliculogenesis and activate the anagen growing phase of dormant bulbs. Interestingly, further studies have revealed that combining PRP with other hair loss-related products may enhance the final performance of the treatment. These synergistic approaches include Food and Drug Administration (FDA) approved drugs such as finasteride or minoxidil, bioactive macromolecules and cell-based therapies. Here, recent research involving alone or combined therapy with platelet-rich plasma for the management of hair loss-related disorders are outlined and future prospects are discussed.

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.

Plasma rich in growth factors membrane as coadjuvant treatment in the surgery of ocular surface disorders

To evaluate the safety and efficacy of the surgical use of plasma rich in growth factors fibrin membrane (mPRGF) in different ocular surface pathologies.Fifteen patients with different corneal and conjunctival diseases were included in the study. Patients were grouped according to the use of mPRGF as graft (corneal and/or conjunctival) or dressing; they were also grouped according to the surgical subgroup of intervention (persistent corneal ulcer [PCU], keratoplasty, superficial keratectomy, corneal perforation, and pterygium). Best corrected visual acuity, intraocular pressure (IOP), inflammation control time (ICT), mPRGF AT (PRGF membrane absorption time), and the healing time of the epithelial defect (HTED) were evaluated throughout the clinical follow-up time. Safety assessment was also performed reporting all adverse events.mPRGF showed a total closure of the defect in 13 of 15 patients (86.7%) and a partial closure in 2 patients (13.3%). The mean follow-up time was 11.1 ± 4.2 (4.8-22.8) months, the mean ICT was 2.5 ± 1.1 (1.0-4.0) months, the mean mPRGF AT was 12.4 ± 2.0 (10.0-16.0) days, and for the global HTED the mean was 2.9 ± 1.2 (1-4.8) months. Results showed an improvement in BCVA in all patients, with an overall improvement of 2.9 in Vision Lines. The BCVA significantly improved (P < .05) in the groups of corneal graft and dressing. In the PCU subgroup (6 patients), the healing time of epithelial defect was significantly reduced (P < .05) in patients treated only with the mPRGF in comparison to those which mPRGF therapy was associated to the amniotic membrane. The IOP remained stable (P > .05) throughout the clinical follow-up time. No adverse events were reported after mPRGF use.The mPRGF is effective and safe as coadjuvant treatment in surgeries related with ocular surface disorders, being an alternative to the use of amniotic membrane. The mPRGF accelerates tissue regeneration after ocular surface surgery thus minimizing inflammation and fibrosis.

Treatment of Dry Eye Disease with Autologous Platelet-Rich Plasma: A Prospective, Interventional, Non-Randomized Study

Introduction

The objective of this study was to evaluate the use of autologous platelet-rich plasma (PRP) eye drops as monotherapy for the treatment of moderate to severe cases of dry eye disease.

Methods

Three hundred and sixty-eight patients with moderate to severe dry eye disease (DED) were included in this prospective case series. Subjects were classified as evaporative DED (EDED) or aqueous deficient DED (ADDED). Improvement of the DED subjective symptoms, corneal fluorescein staining (CFS), and corrected distance visual acuity (BCVA) were evaluated. We also analysed how many rounds of PRP therapy were used.

Results

Two hundred and ninety-seven (80.7%) patients were women, and 71 (19.3%) were men. Two hundred and thirty-two (63%) patients had EDED, while 136 (37%) had ADDED. After 6 weeks of monotherapy treatment with autologous PRP, dry eye symptoms improved in 322 (87.5%) cases. A decrease of CFS was observed in 280 (76.1%) patients. One hundred and six (28.8%) patients improved at least 1 line of BCVA. The scores in the ocular Surface Disease Index and the Oxford scale of corneal fluorescein staining decreased statistically after the treatment (p < 0.05).

Conclusion

The topical use of autologous platelet-rich plasma as monotherapy is an effective treatment to improve signs and symptoms in patients suffering from moderate to severe chronic DED.

Deep anterior lamellar keratoplasty of dog eyes using the big-bubble technique

This study was conducted to establish the feasibility of corneal transplantation using the big-bubble technique (BBT) to perform deep anterior lamellar keratoplasty (DALK) in three dogs. After the cornea was trephined 750 µm, 4 mL of air was injected, and the blanched stroma was removed to expose Descemet's membrane (DM). The donor corneal button, which was gently stripped off the DM, was sutured onto the bare DM of the recipient cornea. The dogs received topical antibiotics every 6 h for 7 days and 2% cyclosporine ointment every 12 h for 1 month. The eyes were examined post-operatively at 7, 14, 21, 28 and 150 days. The central portion of the transplanted cornea stayed transparent while corneal haze developed around the transplanted margin. Menace response was normal even though the transplanted cornea was edematous until 3 weeks after surgery. A marginal haze was rarely observed between the donor and recipient corneas at 150 days after the operation. A spotted haze developed in the central part of the deep stroma near the DM. Upon histopathological examination, the stroma and epithelium of the donor cornea had normal structures. Corneal transplantation using DALK with BBT can be performed in dogs preserving the healthy endothelium.

Platelet rich plasma in ocular surface

The use of platelet-rich preparations has experienced a significant increase in recent years due to its role in tissue-repair and regeneration. The aim of this study is to examine the available evidence regarding the application of plasma rich in growth factors, and its variations, on the ocular surface. A review is also presented on the effects of platelet-derived growth factors, the implications of the preparation methods, and the existing literature on the safety and efficacy of these therapies in ocular surface diseases. Despite the widespread use of platelet preparations there is no consensus on the most appropriate preparation method, and growth factors concentration vary with different systems. These preparations have been used in the treatment of ocular surface diseases, such as dry eye or persistent epithelial defects, among others, with good safety and efficacy profiles, but further studies are needed to compare to the currently available alternatives.

Argus II retinal prosthesis implantation with scleral flap and autogenous temporalis fascia as alternative patch graft material: a 4-year follow-up

Introduction

The Argus II retinal prosthesis is composed of an epiretinal electrode array positioned over the macula and connected to an extrascleral electronics case via a silicone cable, running through a sclerotomy. During implantation, the manufacturer recommends to cover the sclerotomy site with a patch of processed human pericardium to prevent postoperative hypotony and conjunctival erosion by the underlying electronics case. Due to biomedical regulations prohibiting the use of this material in France, we developed an alternative technique combining a scleral flap protecting the sclerotomy and an autogenous graft of superior temporalis fascia overlying the electronics case.

Methods

The purpose of this study is to describe the 4-year outcomes of this modified procedure in three subjects who underwent Argus II Retinal Prosthesis System implantation. Clinical data consisting of intraocular pressure measurements and tolerance in terms of conjunctival erosion or inflammation were retrospectively assessed over a 4-year postoperative follow-up.

Results

None of the three patients implanted with the modified technique developed ocular hypotony over 4 years. A normal, transient conjunctival inflammation occurred during the first postoperative month but conjunctival erosion was not observed in any of the three patients over 4 years. Four years after implantation, the autogenous temporalis fascia graft remained well tolerated and the retinal prosthesis was functional in all three patients.

Conclusion

The combination of an autograft of superficial temporalis fascia and a scleral flap efficiently prevented leakage through the sclerotomy site, ocular hypotony, and conjunctival erosion by the extrascleral electronics case. This modified technique is suitable for the implantation of existing and forthcoming retinal prostheses. Superficial temporalis fascia may also be used as alternative to commercial tectonic tissues for scleral wound repair in clinical settings where they are not available.

Solid Platelet Rich Plasma in Corneal Surgery

Abstract

Solid eye platelet-rich plasma (E-PRP) concentrates platelets in a small volume of plasma which contains a high concentration of important growth factors and cell adhesion molecules. These cell adhesion molecules and growth factors occupy a major role in wound healing and enhance the physiological procedure at the site of the injury or the surgery. There are different materials used to tectonically maintain the solid clot attached at the site where treatment is necessary. Although AM may be used for this purpose, other biomaterials such a bovine pericardium or autologous fibrin membrane are at least as effective with less interdonor variations, no biological hazards, providing a better surgical alternative than the biologically so variable amniotic membrane patch. Solid platelet-rich plasma in the form obtained in ophthalmology, E-PRP, is a reliable and effective surgical coadjuvant to promote corneal wound healing in severe corneal ulcers and corneal perforations, and may be associated with other ocular surface reconstruction procedures.

Funding

Supported in part by a grant from the Spanish Ministry of Science and Innovation, Centro para el Desarrollo Tecnológico Industrial (CDTI), CENIT: “Customized Eye Care”, CeyeC (CEN-20091021).

Plasma Rich in Growth Factors for the Treatment of Ocular Surface Diseases

PURPOSE

The purpose of this work is to describe and review the technology of plasma rich in growth factors (PRGF), a novel blood derivative product, in the treatment of ocular surface disorders.

METHODS

To demonstrate the importance of this technology in the treatment of ocular pathologies, a thorough review of the preclinical and clinical literature results obtained following use of the different therapeutic formulations of PRGF was carried out. A literature search for applications of PGRF plasma in the ophthalmology field was carried out using the PubMed database.

RESULTS

PRGF involves the use of patient's own biologically active proteins, growth factors, and biomaterial scaffolds for therapeutic purposes. This procedural technology is gaining interest in regenerative medicine due to its potential to stimulate and accelerate the tissue healing processes. The versatility and biocompatibility of this technology opens the door to a personalized medicine on ocular tissue regeneration. This review discusses the state of the art of the new treatments and technologies developed to promote ocular surface tissue regeneration. The standardized protocol that has been developed to source eye drops from PRGF technology is also described. The preclinical research, together with the most relevant clinical applications are summarized and discussed.

CONCLUSIONS

The preliminary results suggest that the use of PRGF to enhance ocular tissue regeneration is safe and efficient.

Autologous serum and plasma rich in growth factors in ophthalmology: preclinical and clinical studies

The use of blood derivatives represents an alternative therapeutic approach that is gaining interest in regenerative medicine due to its potential to stimulate and accelerate tissue healing. Autologous serum eye drops and platelet-enriched plasma eye drops are being used in the treatment of different ophthalmological disorders. In this review, we summarize the different blood-derived formulations used in the treatment and care of ocular surface disorders. The biological basis and use of autologous serum and plasma rich in growth factors are deeply evaluated as well as the challenges to be addressed in the future in this new generation of blood-derived therapies.

Eye platelet-rich plasma in the treatment of ocular surface disorders

PURPOSE OF REVIEW

Blood-derived products [autologous serum, eye platelet-rich plasma (E-PRP), plasma rich in growth factors] are successful therapies for ocular surface disorders, which compromise the integrity of the cornea surface and conjunctiva.

RECENT FINDINGS

The most noteworthy and recent research has been directed towards hemoderivatives that include platelets. PRP for ophthalmologic use (E-PRP) has achieved successful outcomes as reported in the peer-review literature in the treatment of dry eye, post-laser in-situ keratomileusis ocular surface syndrome, dormant ulcers, and for ocular surface surgical reconstruction after corneal perforation associated to amniotic membrane transplantation, bovine pericardium membrane transplantation, or autologous fibrin membrane combined with solid PRP clot.

SUMMARY

PRP is a portion of the patient's own blood having a platelet concentration above baseline. The main advantage of PRP over other products is the presence of the platelets and associated with this the prolonged release of growth factors that are involved in the wound healing process of the cornea and conjunctival surface. E-PRP seems to be a reliable and effective therapeutic approach to enhance epithelial wound healing and promote ocular surface regeneration in different pathological conditions.

Ophthalmic use of blood-derived products

There is a wide spectrum of blood-derived products that have been used in many different medical and surgical specialties with success. Blood-derived products for clinical use can be extracted from autologous or allogeneic specimens of blood, but recombinant products are also commonly used. A number of blood derivatives have been used for a wide range of ocular conditions, from the ocular surface to the retina. With stringent preparation guidelines, the potential risk of transmission of blood-borne diseases is minimized. We review blood-derived products and how they are improving the management of ocular disease.