Progress in the use of plasma rich in growth factors in ophthalmology: from ocular surface to ocular fundus

Safety of intraoperative autologous plasma incubation of corneal grafts for reducing endothelial cell loss: a pilot study

Background/aims

Corneal endothelial cell loss contributes to transplant failure. Autologous plasma products (APP) activate salvaging pathways that can prevent oxidative stress perioperatively. This study aimed to evaluate the safety of intraoperative incubation of full-thickness corneal grafts in platelet-rich plasma (aPRP) and plasma rich in growth factors (PRGF-Endoret) in mitigating postoperative corneal endothelial cell loss (ECL).

Methods

Pilot study including patients undergoing penetrating keratoplasty (PK) for various indications between June 2021 and December 2022. Patients were randomly assigned to receive either aPRP or PRGF-Endoret incubation, while those who declined intervention served as the control group. Demographic and clinical data were collected, including preoperative and postoperative endothelial cell count, intraocular pressure, pachymetry, and adverse reactions.

Results

Thirty individuals who underwent PK completed follow-up: eight from the aPRP group, 10 from the PRGF-Endoret group, and 12 from the control group. No adverse events related to APP treatment were recorded. In the first and third postoperative months, the APP group had significantly lower ECL percentages (37% vs. 25%, p = 0.02, and 44% vs. 33%, p = 0.02, respectively); this trend was maintained in the sixth month. When stratified, the PRGF-Endoret group showed significant differences in ECL reduction compared to controls at both time points (p = 0.03 and p = 0.05, respectively). The aPRP group showed a similar statistically significant outcome exclusively on the third postoperative month (p = 0.04). APP tended to reduce corneal edema faster than controls. Hexagonality was significantly better in the APP groups in the first and third months, particularly in the PRGF-Endoret group (p < 0.005).

Conclusion

Preoperative incubation with APP is safe and promotes better endothelial cell quality and quantity in the early postoperative period following PK. These findings suggest a potential clinical benefit in enhancing graft outcomes and warrant further investigation.

Plasma rich in growth factors (PRGF) technology as adjuvant to Ab Externo trabeculectomy

PURPOSE

Plasma rich in growth factors (PRGF) technology creates blood-derived products with growth factors that promote wound healing and regeneration. The goal of this study was to assess the potential role of PRGF products as wound modulators in trabeculectomy. Our premise is that due to PRGF's regenerative and antifibrotic properties, its use in trabeculectomy may produce a more physiological bleb, without altering IOP reduction.

METHODS

A retrospective, longitudinal study was conducted in a Hospital in Portugal. Patients with eyes with open angle glaucoma were included. Trabeculectomy was performed on all patients using PRGF membrane (mPRGF) under the conjunctiva, as adjuvant. Data regarding patients' demographics and number of medications used, was collected. Intraocular pressure (IOP) before surgery, 8 days, 1 month, 3 month, 6 month, 9 month and 1 year after surgery was recorded. Bleb morphology was classified according to Moorfields Bleb Grading System 6 months after surgery.

RESULTS

Nine eyes of 9 patients were enrolled. Mean age was 71 ± 5.1 years old. Six were male. Mean IOP decreased from 24.0 ± 8.8 mmHg pre-surgery to 12.9 ± 2.6 mmHg at one year follow-up. The number of hypotensive drugs (mean ± SD) was 4.3 ± 0.9 preoperatively and 0.8 ± 1.1 at 1-year. Complete success was defined as IOP equal to or less than 21 mm Hg without ocular hypotensive medications and qualified success as IOP equal to or less than 21 mm Hg with medications. Complete success was 66.7% and qualified success was 100% at 1 year follow-up.

CONCLUSION

In our study, trabeculectomy with mPRGF demonstrated both safety and efficacy. Low values of bleb height (1.6 ± 0.8) were recorded. mPRGF could improve wound healing and produce a more well-tolerated, favourable bleb, avoiding antimetabolite complications.

Platelet-derived biomaterial controls aspergillus fumigatus keratitis by decreasing fungal burden: an in vivo study

Fungal keratitis is a severe corneal infection characterized by suppurative and ulcerative lesions. Aspergillus fumigatus is a common cause of fungal keratitis. Antifungal drugs, such as natamycin, are currently the first-line treatment for fungal keratitis, but their ineffectiveness leads to blindness and perforation. Additionally, the development of fungal resistance makes treating fungal keratitis significantly more challenging. The present study used platelet-derived biomaterial (PDB) to manage A. fumigatus keratitis in the animal model. Freezing and thawing processes were used to prepare PDB, and then A. fumigatus keratitis was induced in the mice. Topical administration of PDB, natamycin, and plasma was performed; quantitative real-time PCR (qPCR) and histopathologic examination (HE) were used to assess the inhibitory effect of the mentioned compounds against fungal keratitis. The qPCR results showed that PDB significantly decreased the count of A. fumigatus compared to the control group (P-value ≤ 5). Natamycin also remarkably reduced the count of fungi in comparison to the untreated animal, but its inhibitory effect was not better than PDB (P-value > 5). The findings of HE also demonstrated that treatment with PDB and natamycin decreased the fungal loads in the corneal tissue. However, plasma did not show a significant inhibitory effect against A. fumigatus. PDB is intrinsically safe and free of any infections or allergic responses; additionally, this compound has a potential role in decreasing the burden of A. fumigatus and treating fungal keratitis. Therefore, scientists should consider PDB an applicable approach to managing fungal keratitis and an alternative to conventional antifungal agents.

Not all platelet-rich plasma are created equal

PURPOSE OF REVIEW

This review aims to elucidate potential variations in clinical outcomes resulting from the use of different types of platelet-rich plasma (PRPs) in reproductive medicine. It seeks to explore the reasons behind the diverse results reported in various studies and assess the general features distinguishing different PRP formulations.

RECENT FINDINGS

PRPs have found applications across diverse medical fields, generating controversy due to the variability in outcomes. The field of reproductive medicine, despite its limited published studies, is encountering a similar challenge as it integrates these treatments.

SUMMARY

The multitude of PRP product brands in the market, coupled with 'home-made' PRPs, poses a significant barrier to establishing a common protocol for the preparation of standardized PRP products. This impediment hinders widespread adoption by clinicians, particularly in endometrial or ovarian treatments. Drawing from evidence in other medical disciplines, this review endeavors to compile essential characteristics that PRPs must possess, aiming to mitigate the impact of variables affecting results in forthcoming studies.

Blood-Derived Eye Drops for the Treatment of Corneal Neuropathic Pain

Blood-derived preparations, including autologous or allogenic serum, umbilical cord serum/plasma, and platelet-rich plasma eye drops, contain various growth factors, cytokines, and immunoglobulins that resemble natural tears. These components play important roles in corneal cell migration, proliferation, and wound healing. Blood-derived eye drops have demonstrated clinical effectiveness across a spectrum of ocular surface conditions, encompassing dry eye disease, Sjögren's syndrome, graft-versus-host disease, and neuropathic corneal pain (NCP). Currently, management of NCP remains challenging. The emergence of blood-derived eye drops represents a promising therapeutic approach. In this review, we discuss the benefits and limitations of different blood-derived eye drops, their mechanisms of action, and treatment efficacy in patients with NCP. Several studies have demonstrated the clinical efficacy of autologous serum eye drops in relieving pain and pain-like symptoms, such as allodynia and photoallodynia. Corneal nerve parameters were also significantly improved, as evidenced by increased nerve fiber density, length, nerve reflectivity, and tortuosity, as well as a decreased occurrence of beading and neuromas after the treatment. The extent of nerve regeneration correlated with improvement in patient-reported photoallodynia. Cord plasma eye drops also show potential for symptom alleviation and corneal nerve regeneration. Future directions for clinical practice and research involve standardizing preparation protocols, establishing treatment guidelines, elucidating underlying mechanisms, conducting long-term clinical trials, and implementing cost-effective measures such as scaling up manufacturing. With ongoing advancements, blood-derived eye drops hold promise as a valuable therapeutic option for patients suffering from NCP.

Addressing corneal opacity after herpes zoster infection

A 15-year-old boy was referred for corneal opacity evaluation. The patient had a previous herpes zoster virus (HZV) infection-varicella-zoster virus (VZV)-with ocular manifestation 1 year ago. After the infection, he developed a central corneal scar and decreased corrected distance visual acuity (CDVA) in the right eye. The slitlamp examination showed the right eye with central corneal opacity (involving anterior stroma), lacuna area between the haze, fluorescein negative, and no vascularization near the scar (Figure 1JOURNAL/jcrs/04.03/02158034-202406000-00019/figure1/v/2024-07-10T174224Z/r/image-tiff). The patient had been treated with oral valacyclovir and topical corticosteroids without any improvement of visual acuity or changes in opacity within the 1-year follow-up. His CDVA was 20/200 (-4.50 -0.75 × 25) in the right eye and counting fingers (-4.00) in the left eye. Intraocular pressure was 12 mm Hg in both eyes. Fundoscopy was normal in the right eye, but he had a macular scar in the left eye (diagnosed when he was 7 years). The left eye had no cornea signs. The patient has no comorbidity or previous surgeries. Considering this case, a corneal central scar in a 15-year-old boy, legally single eye only, and assuming it is an opacity in the anterior stroma, would you consider surgery for this patient? If so, which would you choose: Would you consider an excimer laser treatment of his ametropia while partially removing his opacity, a phototherapeutic keratectomy (PTK), or a PTK followed by a topography-guided treatment, femtosecond laser-assisted anterior lamellar keratoplasty (FALK), or deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (depending on the scar depth)? Would you consider prophylactic acyclovir during and after surgery? Would you consider any other surgical step to prevent delayed corneal healing-persistent epithelial defect? Before the surgical approach, would you consider treating this patient with topical losartan (a transforming growth factor [TGF]-β signaling inhibitor)? Would you first perform the surgery (which one) and then start the medication? Furthermore, if so, how long would you treat this patient? Would you consider treatment with another medication?

Autologous Platelet-rich Fibrin as a Three-dimensional Structural Scaffold in the Healing of Contracted Orbital Sockets

PURPOSE

Evaluation of platelet-rich fibrin as an adjuvant in surface healing of contracted orbital sockets.

METHODS

Prospective, interventional, and comparative study of 25 patients with moderate to severe contracted sockets conducted over 2 years (February 2020-February 2022). Group 1 underwent a dermis-fat graft with fornix forming sutures supplemented by a platelet-rich fibrin membrane, while group 2 received a dermis-fat graft with fornix forming sutures only. Patients over 18 years were evaluated as per prefixed inclusion and exclusion criteria. Assessments were conducted at 1, 3, and 12 months postsurgery, focusing on wound evaluation, socket epithelialization, postoperative pain, prosthesis rehabilitation, and complications, if any. Wound evaluation and pain intensity were assessed utilizing the wound evaluation score and visual analog scale, respectively. Socket epithelization was documented clinically at every visit.

RESULTS

The study showed a mean age of 38.8 ± 8.8 years, with a 2:1 male-to-female ratio. Group 1 consistently scored higher on wound evaluation score than group 2 at all follow-up points. In group 1, 81.8% achieved a maximum wound evaluation score at 4 weeks and 100% at 3 and 12 months, compared to group 2's 42.8%, 50%, and 57.1%, respectively (p < 0.05). Postoperative contracture occurred in 3 group 2 patients at the final follow-up, with 6 showing unsatisfactory appearance. Group 1 demonstrated significantly lower pain intensity on postoperative day 1 (p = 0.03), and greater epithelization at 4 weeks.

CONCLUSION

platelet-rich fibrin appears to be an effective solution for enhancing wound healing during socket reconstruction, attributed to its sustained release of growth factors and mesenchymal stem cells.

How to explain the beneficial effects of platelet-rich plasma

Platelet-rich plasma (PRP) is the platelet and leukocyte-containing plasmatic fraction of anticoagulated autologous blood. While evidence supporting the clinical use of PRP in dentistry is low, PRP is widely used in sports medicine, orthopedics, and dermatology. Its beneficial activity is commonly attributed to the growth factors released from platelets accumulating in PRP; however, evidence is indirect and not comprehensive. There is thus a demand to revisit PRP with respect to basic and translational science. This review is to (i) recapitulate protocols and tools to prepare PRP; (ii) to discuss the cellular and molecular composition of PRP with a focus on platelets, leukocytes, and the fibrin-rich extracellular matrix of coagulated plasma; and finally (iii) to discuss potential beneficial effects of PRP on a cellular and molecular level with an outlook on its current use in dentistry and other medical fields.

Platelet-rich plasma for treating dry eye disease - A systematic review and meta-analysis

PURPOSE

Dry eye disease has public health and economic significance. Platelet-rich plasma is rich in anti-inflammatory agents and growth factors, both beneficial for ocular surface repair. This study aimed to conduct a systematic review and meta-analysis to summarize the benefits of platelet-rich plasma for treating dry eye disease and its adverse effects.

METHODS

Prospective comparative studies using platelet-rich plasma as monotherapy for dry eye disease were included for efficacy assessment. Before-after studies were included for adverse events assessment. Data sources included PubMed, Google Scholar, Web of Science, and Scopus. A systematic review and meta-analysis protocol was pre-registered on PROSPERO (CRD42022347982). PRISMA guidelines were followed. The National Health Institute (NIH) quality assessment tool for before-after studies, the Cochrane risk of bias tool (RoB2), and the methodological index for non-randomized studies were used to assess the risk of bias. Heterogeneity was assessed using the I2 statistic.

RESULTS

19 studies (10 comparative and 9 before-after) were included in the systematic review and meta-analysis. The occurrence rate of adverse effects was 2.6 % (95 % CI: 0.5 - 4.7). The pooled standardized mean difference (SMD) for dry eye symptoms was 0.81 (95 % CI: 0.25 - 1.37; I2 = 82 %; p < 0.00001; Z = 2.84, p = 0.004); tear quality was 0.44 (95 % CI: 0.06 - 0.81; I2 = 67 %; p = 0.003; Z = 2.26, p = 0.02); tear quantity was 0.45 (95 % CI: 0.03 - 0.88; I2 = 74 %; p = 0.0003; Z = 2.10, p = 0.04); and corneal staining 0.72 (95 % CI: 0.14 - 1.30; I2 = 85 %; p < 0.00001; Z = 2.43, p = 0.02).

CONCLUSION

The current study shows that platelet-rich plasma is efficacious in managing dry eye disease, significantly reducing dry eye signs and symptoms. Such significant improvements could translate to improved quality of life.

An effective method for culturing functional human corneal endothelial cells using a xenogeneic free culture medium

Endothelial dysfunction is a leading cause of corneal blindness in developed countries and the only available treatment is the endothelial transplantation. However, the limited availability of suitable donors remains a significant challenge, driving the exploration of alternative regenerative therapies. Advanced Therapy Medicinal Products show promise but must adhere to strict regulations that prohibit the use of animal-derived substances. This study investigates a novel culture methodology using Plasma Rich in Growth Factors (PRGF) as the only source of growth factors for primary cultures of human corneal endothelial cells (CECs). CECs were obtained from discarded corneas or endothelial rings and cultured in two different media: one supplemented with xenogeneic factors and other xenogeneic-free, using PRGF. Comprehensive characterization through immunofluorescence, morphological analyses, trans-endothelial electrical resistance measurements, RNA-seq, and qPCR was conducted on the two groups. Results demonstrate that CECs cultured in the xenogeneic-free medium exhibit comparable gene expression, morphology, and functionality to those cultured in the xenogeneic medium. Notably, PRGF-expanded CECs share 46.9% of the gene expression profile with native endothelium and express all studied endothelial markers. In conclusion, PRGF provides an effective source of xenogeneic-free growth factors for the culture of CECs from discarded corneal tissue. Further studies will be necessary to demonstrate the applicability of these cultures to cell therapies that make clinical translation possible.

Biological and Adhesive Properties of an Autologous Protein-Based Fibrin Sealant for Ophthalmological Applications

Purpose

The aim of this study was to evaluate the biological and adhesive properties of a new autologous sealant based on plasma rich in growth factors (PRGF), named E-Sealant.

Methods

Conventional PRGF and a commercial fibrin sealant (Tisseel) were included as controls. The hematological and protein content of E-Sealant was determined. Its bioactivity and biocompatibility were tested for human keratocytes (HKs). To evaluate its adhesion and regenerative capacity, E-Sealant was used on an animal model of conjunctival autograft surgery and compared to Tisseel.

Results

E-Sealant presented a high growth factor content with levels similar to those of conventional PRGF. E-Sealant induced proliferative and migratory activity on HK cells equivalent to PRGF. Although autologous membranes induced the proliferation of HKs, cells cultured over Tisseel did not adhere nor proliferate. HK cells showed increased number and flattened morphology over PRGF and E-Sealant compared to scarce and round-shape cells detected in Tisseel. Conjunctival autograft glued with E-Sealant adhered successfully, whereas Tisseel application formed irregular clots. During follow-up, both adhesives showed good integration and no dehiscence. However, Tisseel-treated samples presented slightly increased hemorrhage and inflammation. In contrast to Tisseel, E-Sealant-treated autografts presented a continuous layer of non-keratinized stratified squamous epithelium. Inflammatory infiltrates were minimal in E-Sealant-treated conjunctiva, whereas the Tisseel group showed noticeable immune reactions. Unlike Tisseel-treated grafts, E-Sealant presented low immunoreactivity for smooth muscle actin (SMA), suggesting decreased fibrotic tissue formation.

Conclusions

E-Sealant presents optimal biological and adhesive properties suitable for use as an ophthalmic glue, with regenerative purposes superior to commercial fibrin sealants.

Translational Relevance

Our study analyzed the characterization and biological activity of a new autologous fibrin sealant in ocular surface cells and in an animal model in which the adhesive and regenerative properties of the fibrin sealant were evaluated.

PRGF Membrane with Tailored Optical Properties Preserves the Cytoprotective Effect of Plasma Rich in Growth Factors: In Vitro Model of Retinal Pigment Epithelial Cells

The present study evaluates the ability of a novel plasma rich in growth factors (PRGF) membrane with improved optical properties to reduce oxidative stress in retinal pigment epithelial cells (ARPE-19 cells) exposed to blue light. PRGF was obtained from three healthy donors and divided into four main groups: (i) PRGF membrane (M-PRGF), (ii) PRGF supernatant (S-PRGF), (iii) platelet-poor plasma (PPP) membrane diluted 50% with S-PRGF (M-PPP 50%), and (iv) M-PPP 50% supernatant (S-PPP 50%). ARPE-19 cells were exposed to blue light and then incubated with the different PRGF-derived formulations or control for 24 and 48 h under blue light exposure. Mitochondrial and cell viability, reactive oxygen species (ROS) production, and heme oxygenase-1 (HO-1) and ZO-1 expression were evaluated. Mitochondrial viability and cell survival were significantly increased after treatment with the different PRGF-derived formulations. ROS synthesis and HO-1 expression were significantly reduced after cell treatment with any of the PRGF-derived formulations. Furthermore, the different PRGF-derived formulations significantly increased ZO-1 expression in ARPE-19 exposed to blue light. The new PRGF membrane with improved optical properties and its supernatant (M-PPP 50% and S-PPP 50%) protected and reversed blue light-induced oxidative stress in ARPE-19 cells at levels like those of a natural PRGF membrane and its supernatant.

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.

Plasma Rich in Growth Factors as an Adjuvant Agent in Non-Penetrating Deep Sclerectomy

BACKGROUND

The purpose of this study is to evaluate the utility and safety of plasma rich in growth factors immunosafe eye drops (is-ePRGF) in the postoperative treatment of non-penetrating deep sclerectomy (NPDS).

METHODS

This is a case-control study in patients with open-angle glaucoma. Group one (control) was not treated with is-ePRGF, while group two (is-ePRGF) was treated (four times a day for four months). Postoperative evaluations were performed at one day, one month, three months and six months. The main outcomes were: intraocular pressure (IOP), microcysts in blebs with AS-OCT and the number of hypotensive eye drops.

RESULTS

Preoperatively, group one (n = 48 eyes) and group two (n = 47 eyes) were similar in age (71.5 ± 10.7 vs. 70.9 ± 10.0 years; p = 0.68), IOP (20.6 ± 10.2 vs. 23.0 ± 9.0 mmHg; p = 0.26) and number of hypotensive drugs (2.7 ± 0.8 vs. 2.8 ± 0.9; p = 0.40). The IOP at six months dropped to 15.0 ± 8.0 mmHg (IOP reduction: -27.2%) and 10.9 ± 4.3 mmHg (IOP reduction: -52.6%) for group one and group two, respectively (p < 0.01). At six months, blebs with microcysts were 62.5% (group one) and 76.7% (group two). Postoperative complications were observed in 12 eyes (25%) for group one and in 5 eyes (11%) for group two (p = 0.06). No specific complications related to the use of is-ePRGF were identified.

CONCLUSIONS

Topical is-ePRGF seems to reduce IOP and the rate of complications in the medium term after NPDS, so it can be considered as a possible safe adjuvant to achieve surgical success.

The Short-Term Results of Autologous Platelet-Rich Plasma as an Adjuvant to Re-Intervention in the Treatment of Refractory Full-Thickness Macular Holes

The purpose of this study was to investigate the short-term efficacy and safety of autologous platelet-rich plasma (a-PRP) as an adjuvant to revisional vitrectomy for refractory full-thickness macular holes (rFTMHs). We conducted a prospective, non-randomized interventional study including patients with rFTMH after a pars plana vitrectomy (PPV) with internal limiting membrane peeling and gas tamponade. We included 28 eyes from 27 patients with rFTMHs: 12 rFTMHs in highly myopic eyes (axial length greater than 26.5 mm or a refractive error greater than -6D or both); 12 large rFTMHs (minimum hole width > 400 μm); and 4 rFTMHs secondary to the optic disc pit. All patients underwent 25-G PPV with a-PRP, a median time of 3.5 ± 1.8 months after the primary repair. At the six-month follow-up, the overall rFTMH closure rate was 92.9%, distributed as follows: 11 out of 12 eyes (91.7%) in the highly myopic group, 11 out of 12 eyes (91.7%) in the large rFTMH group, and 4 out of 4 eyes (100%) in the optic disc pit group. Median best-corrected visual acuity significantly improved in all groups, in particular from 1.00 (interquartile range: 0.85 to 1.30) to 0.70 (0.40 to 0.85) LogMAR in the highly myopic group (p = 0.016), from 0.90 (0.70 to 1.49) to 0.40 (0.35 to 0.70) LogMAR in the large rFTMH group (p = 0.005), and from 0.90 (0.75 to 1.00) to 0.50 (0.28 to 0.65) LogMAR in the optic disc pit group. No intraoperative or postoperative complications were reported. In conclusion, a-PRP can be an effective adjuvant to PPV in the management of rFTMHs.

Ocular Surface Disease in Glaucoma Patients

PURPOSE

To review the most recent studies in the literature regarding the ocular surface in glaucoma patients and treatment options aimed to reduce ocular surface disease in this population.

METHODS

We performed a literature search in the electronic databases of PubMed CENT RAL, Google Scholar, EMBASE the Register of Controlled Trials, and Ovid MEDLINE using the following terms: "ocular surface", "dry eye", "glaucoma", "selective laser trabeculoplasty", "glaucoma surgery", "preservatives", "preservative free", "ocular surface disease index", "tear break up time", "MMP-9" and "conjunctival hyperemia".

RESULTS

Over the last several years, several studies have demonstrated the changes to the ocular surface in the setting of glaucoma, the best tests for markers of dry eye, and how management can be altered to help address ocular surface disease routinely or in preparation for glaucoma surgery.

CONCLUSION

Ocular surface disease in the glaucoma patient population is widely recognized. It should be addressed to maximize patient compliance and quality of life.

Development of a new plasma rich in growth factors membrane with improved optical properties

PURPOSE

The aim of the present work was to develop a fibrin membrane using plasma rich in growth factors (PRGF) technology with improved optical properties to be used for the treatment of ocular surface diseases.

BASIC PROCEDURES

Blood was drawn from three healthy donors, and the volume of PRGF obtained from each donor was divided into two main groups: i) PRGF or ii) platelet-poor plasma (PPP). Each membrane was then used pure or diluted to 90 %, 80 %, 70 %, 60 % and 50 %. The transparency of each of the different membranes was evaluated. The degradation and morphological characterization of each membrane was also performed. Finally, a stability study of the different fibrin membranes was performed.

MAIN FINDINGS

The transmittance test showed that the fibrin membrane with the best optical characteristics was obtained after removal of platelets and dilution of fibrin to 50 % (50 % PPP). No significant differences (p > 0.05) were observed between the different membranes in the fibrin degradation test. The stability test showed that the membrane at 50 % PPP retains its optical and physical characteristics after storage at - 20 °C for 1 month compared to storage at 4 °C.

PRINCIPAL CONCLUSIONS

The present study describes the development and characterization of a new fibrin membrane with improved optical characteristics while maintaining mechanical and biological characteristics. The physical and mechanical properties of the newly developed membrane are preserved after storage for at least 1 month at - 20 °C.

The use of platelet-rich plasma and two-component autofibrin glue in treatment of experimental chronic persistent corneal erosion

BACKGROUND: The use of platelet-rich plasma (PRP) and its modifications are a promising treatment method for chronic inflammatory diseases of the cornea. AIM: To evaluate and compare the clinical and morphological features of the corneal regeneration during experimental chronic persistent corneal erosion with the use of PRP and two-component autofibrin glue (TAFG). MATERIALS AND METHODS: The studies were conducted in 18 rabbits (36 eyes). After modeling chronic persistent corneal erosion, the animals of the 1st group were treated with TAFG; animals of the 2nd group with instillations of PRP, animals of the 3rd group with standard medical therapy. RESULTS: By Day 14 of the experiment, the restoration of the transparency of the cornea, no erosion and new vessels in animals of the 1st and 2nd group were noted. This pattern persisted until Day 60. By Day 30 of the experiment, the presence of corneal clouding in optical zone, neovascularization over the whole cornea and an epithelial defect (3,85 [3,50; 4,47] %) in animals of the 3rd group were recorded. By Day 60, a complete epithelialization of the cornea was observed. CONCLUSIONS: The use of PRP and TAFG allows reducing the time of corneal epithelialization by 2,5 times in conditions of experimental chronic persistent corneal erosion. There were no significant differences between the use of PRP (within 5 days) and TAFG, however, treatment with an adhesive composition is more convenient for both the doctor and the patient a single use that does not require multiple use of expensive consumable materials.

Beneficial Effects of Plasma Rich in Growth Factors (PRGF) Versus Autologous Serum and Topical Insulin in Ocular Surface Cells

PURPOSE

In the last few decades, several blood derived products such as platelet-rich plasma (PRP), plasma rich in growth factors (PRGF) and autologous serum (AS) have been used for the treatment of ocular surface disorders. Recently, insulin has been proposed to be used as an alternative for the treatment of ocular surface diseases. The aim of this study was to evaluate the biological potential of PRGF eye drops in comparison with AS and insulin on ocular surface cells.

METHODS

Blood from three healthy young donors was collected to obtain autologous serum (AS) eye drops and plasma rich in growth factors (PRGF) eye drops. Insulin (Actrapid^®) was diluted at 1 and 0.2 IU/mL. The biological potential of PRGF, AS and insulin was assessed by proliferation in HCE, HK and HConF cells. Wound healing assay was performed in HCE cells after incubation with the different treatments. HConF and HK cells were differentiated to myofibroblast after treatment with 2.5 ng/mL of TGF-β1 and then incubated with all treatments.

RESULTS

PRGF eye drops induced significantly higher proliferation rate compared to AS or insulin in HConF and HK cells, but not in HCE cells. In addition, the percentage of wound healing area was significantly reduced after PRGF treatment in comparison with AS or insulin treatment. Furthermore, PRGF significantly reduced the number of myodifferentiated cells compared to AS and insulin at both concentrations analyzed.

CONCLUSION

The results obtained in the present study show that PRGF increases the biological activity of the ocular surface cells and reduces the expression of fibrosis marker compared to insulin or AS.

TRANSLATIONAL RELEVANCE

The present study suggests that plasma rich in growth factors eye drops are a more effective therapy than insulin and autologous serum eye drops for the treatment of ocular surface diseases.

Progress on the application of growth factor-related drugs in ophthalmology

Vascular endothelial growth factor（VEGF）, fibroblast growth factor（FGF）, nerve growth factor（NGF）, epidermal growth factor and interferon are important endogenous proteins that regulate cell proliferation, differentiation and regeneration. Biological products targeting growth factors are used in the treatment of ocular diseases such as wet age-related macular degeneration, corneal injury and neurotrophic keratitis. Anti-VEGF drugs can regulate the proliferation of vascular endothelia, reduce the edema and exudation of retinal tissue，which are the main therapeutic agents for wet age-related macular degeneration and diabetic retinopathy. The basic FGF (b-FGF) can promote the proliferation, differentiation, and migration of corneal epithelial cells, accelerating the healing of the corneal injury and reduces corneal inflammation；and bovine b-FGF has been approved for the treatment of corneal injuries. The NGF promotes the growth, development, and differentiation of central and peripheral neurons, thus accelerating the repair of nerve damage；and the European Medicines Agency approved the use of nerve growth factor for the treatment of neurotrophic keratitis in 2017. Recent clinical studies show that patients with moderate or severe neurotrophic keratitis achieved complete corneal healing following 8 weeks of NGF therapy. Epidermal growth factor derivative eye drops have been approved for the treatment of corneal epithelial injuries. Recombinant human interferon has been clinically used in the treatment of ocular viral infections. This article reviews the research progress in the development of new cell growth factor drugs for the treatment of ophthalmic diseases, to provide insights for expanding the application of cell growth factors in ophthalmology.

Optimization of a Plasma Rich in Growth Factors Membrane for the Treatment of Inflammatory Ocular Diseases

The main purpose of the present study is to develop an immunosafe fibrin membrane obtained by plasma rich in growth factors technology (is-mPRGF) with improved mechanical properties that could be applied in patients with inflammatory ocular diseases. Blood was drawn from three healthy donors and centrifuged, and the collected PRGF was activated and distributed into two groups: (i) mPRGF: a PRGF membrane maintained at 37 °C for 30 min; (ii) IS5+30: mPRGF incubated at 37 °C for 5 min and then incubated at 56 °C for 30 min. The content of both membranes was analyzed for several growth factors such as IgE and the complement activation, as well as biological activity on different ocular surface cells. Furthermore, the physical and mechanical characterizations were also evaluated. IS5+30 completely reduced the complement activity and decreased the IgE while preserving the concentration of the main growth factors. IS5+30 induced similar biological activity regarding mPRGF on the different ocular surface cells analyzed. Furthermore, no significant differences in release kinetics or fibrin degradation were observed between both membranes. Summarizing, IS5+30 totally reduces complement activity while preserving the concentration of most growth factors and their biological activity. Furthermore, the physical and mechanical properties of the fibrin membrane are preserved after heat inactivation.

Impact of Freeze-Drying on Cord Blood (CB), Serum (S), and Platelet-Rich Plasma (CB-PRP) Preparations on Growth Factor Content and In Vitro Cell Wound Healing

Blood-based preparations are used in clinical practice for the treatment of several eye disorders. The aim of this study is to analyze the effect of freeze-drying blood-based preparations on the levels of growth factors and wound healing behaviors in an in vitro model. Platelet-rich plasma (PRP) and serum (S) preparations from the same Cord Blood (CB) sample, prepared in both fresh frozen (FF) and freeze-dried (FD) forms (and then reconstituted), were analyzed for EGF and BDNF content (ELISA Quantikine kit). The human MIO-M1 glial cell line (Moorfield/Institute of Ophthalmology, London, UK) was incubated with FF and FD products and evaluated for cell migration with scratch-induced wounding (IncuCyte S3 Essen BioScience), proliferation with cyclin A2 and D1 gene expression, and activation with vimentin and GFAP gene expression. The FF and FD forms showed similar concentrations of EGF and BDNF in both the S and PRP preparations. The wound healing assay showed no significant difference between the FF and FD forms for both S and PRP. Additionally, cell migration, proliferation, and activation did not appear to change in the FD forms compared to the FF ones. Our study showed that reconstituted FD products maintained the growth factor concentrations and biological properties of FF products and could be used as a functional treatment option.

Differential Protein Content between Fresh and Freeze-Dried Plasma Rich in Growth Factors Eye Drops

The purpose of this study was to analyze the proteomic composition of plasma rich in growth factors eye drops (PRGF) in comparison to lyophilized PRGF eye drops (PRGF lyo). The differential protein expression of keratocyte (HK) cells after PRGF or PRGF lyo treatment was also determined. Blood from different donors was collected and processed to obtain PRGF and PRGF lyo eye drops. Then, HK cells were treated with both formulations. A proteomic analysis was performed to evaluate the differential proteomic profile between PRGF and PRGF lyo, and the differential protein expression by HK cells after treatment with both blood-derived products. About 280 proteins were detected between both blood-derived formulation, with only 8 of them reaching significant differences. Furthermore, 101 out of 3213 proteins showed statistically significant deregulation in HK cells after treatment with PRGF or PRGF lyo. Gene Ontology analysis showed that these significant deregulated proteins were involved in 30 functional processes. However, the Ingenuity Pathway Analysis showed that no significant differences were found in any of the identified processes. In summary, the present study show that no significant differences were found in the proteomic profile or in the signaling pathways activation in HK cells between PRGF and PRGF lyo.