Quality standards, safety and efficacy of blood-derived serum eye drops: A review

Multifunctional nano-in-micro delivery systems for targeted therapy in fundus neovascularization diseases

Fundus neovascularization diseases are a series of blinding eye diseases that seriously impair vision worldwide. Currently, the means of treating these diseases in clinical practice are continuously evolving and have rapidly revolutionized treatment opinions. However, key issues such as inadequate treatment effectiveness, high rates of recurrence, and poor patient compliance still need to be urgently addressed. Multifunctional nanomedicine can specifically respond to both endogenous and exogenous microenvironments, effectively deliver drugs to specific targets and participate in activities such as biological imaging and the detection of small molecules. Nano-in-micro (NIM) delivery systems such as metal, metal oxide and up-conversion nanoparticles (NPs), quantum dots, and carbon materials, have shown certain advantages in overcoming the presence of physiological barriers within the eyeball and are widely used in the treatment of ophthalmic diseases. Few studies, however, have evaluated the efficacy of NIM delivery systems in treating fundus neovascular diseases (FNDs). The present study describes the main clinical treatment strategies and the adverse events associated with the treatment of FNDs with NIM delivery systems and summarizes the anatomical obstacles that must be overcome. In this review, we wish to highlight the principle of intraocular microenvironment normalization, aiming to provide a more rational approach for designing new NIM delivery systems to treat specific FNDs.

Current Advances in Regenerative Strategies for Dry Eye Diseases: A Comprehensive Review

Dry eye disease (DED) is an emerging health issue affecting millions of individuals annually. Ocular surface disorders, such as DED, are characterized by inflammation triggered by various factors. This condition can lead to tear deficiencies, resulting in the desiccation of the ocular surface, corneal ulceration/perforation, increased susceptibility to infections, and a higher risk of severe visual impairment and blindness. Currently, the clinical management of DED primarily relies on supportive and palliative measures, including the frequent and lifelong use of different lubricating agents. While some advancements like punctal plugs, non-steroidal anti-inflammatory drugs, and salivary gland autografts have been attempted, they have shown limited effectiveness. Recently, there have been promising developments in the treatment of DED, including biomaterials such as nano-systems, hydrogels, and contact lenses for drug delivery, cell-based therapies, biological approaches, and tissue-based regenerative therapy. This article specifically explores the different strategies reported so far for treating DED. The aim is to discuss their potential as long-term cures for DED while also considering the factors that limit their feasibility and effectiveness. These advancements offer hope for more effective and sustainable treatment options in the future.

New developments in the management of persistent corneal epithelial defects

A persistent epithelial defect (PED) is a corneal epithelial defect that failed to heal after 2weeks. It is a condition that carries much morbidity, and our understanding of PED remains poor, with current treatment methods often having unsatisfactory outcomes. With PEDs becoming more prevalent, more efforts are required to establish reliable treatment modalities. Our reviews describe the causes of PEDs and the different approaches developed to manage them, as well as their associated limitations. Emphasis is placed on understanding various advances in the development of new treatment modalities. We have also described a case of a woman with a background of graft-versus-host disease on long-term topical corticosteroids who developed complicated PED involving both eyes. The current approach to managing PEDs generally involves exclusion of an active infection, followed by treatment modalities that aim to encourage corneal epithelial healing. Success rates, however, remain far from desirable, as treatment remains challenging due to multiple underlying etiologies. In summary, advances in the development of new therapies may be able to facilitate progress in the understanding and treatment of PED.

Expanding applications of allogeneic platelets, platelet lysates, and platelet extracellular vesicles in cell therapy, regenerative medicine, and targeted drug delivery

Platelets are small anucleated blood cells primarily known for their vital hemostatic role. Allogeneic platelet concentrates (PCs) collected from healthy donors are an essential cellular product transfused by hospitals to control or prevent bleeding in patients affected by thrombocytopenia or platelet dysfunctions. Platelets fulfill additional essential functions in innate and adaptive immunity and inflammation, as well as in wound-healing and tissue-repair mechanisms. Platelets contain mitochondria, lysosomes, dense granules, and alpha-granules, which collectively are a remarkable reservoir of multiple trophic factors, enzymes, and signaling molecules. In addition, platelets are prone to release in the blood circulation a unique set of extracellular vesicles (p-EVs), which carry a rich biomolecular cargo influential in cell-cell communications. The exceptional functional roles played by platelets and p-EVs explain the recent interest in exploring the use of allogeneic PCs as source material to develop new biotherapies that could address needs in cell therapy, regenerative medicine, and targeted drug delivery. Pooled human platelet lysates (HPLs) can be produced from allogeneic PCs that have reached their expiration date and are no longer suitable for transfusion but remain valuable source materials for other applications. These HPLs can substitute for fetal bovine serum as a clinical grade xeno-free supplement of growth media used in the in vitro expansion of human cells for transplantation purposes. The use of expired allogeneic platelet concentrates has opened the way for small-pool or large-pool allogeneic HPLs and HPL-derived p-EVs as biotherapy for ocular surface disorders, wound care and, potentially, neurodegenerative diseases, osteoarthritis, and others. Additionally, allogeneic platelets are now seen as a readily available source of cells and EVs that can be exploited for targeted drug delivery vehicles. This article aims to offer an in-depth update on emerging translational applications of allogeneic platelet biotherapies while also highlighting their advantages and limitations as a clinical modality in regenerative medicine and cell therapies.

Maternal serum eye drops to treat bilateral neurotrophic keratopathy in congenital corneal anesthesia: Case report and literature review

Purpose

To report the feasibility and the successful outcomes of a pediatric neurotrophic keratopathy (NK) owing to congenital corneal anesthesia (CCA) treated with allogeneic serum eye drops obtained from the mother as the only therapy.

Observations

A 18-month-old girl with generalized pain insensitivity presented with a large epithelial defect in the right eye (RE) and superficial punctate keratopathy (SPK) in the left eye (LE). Corneal sensitivity was completely absent in both eyes (BE). Peripheral serum eye drops obtained from the mother was prescribed and administered every 2 hours in BE. Two weeks after the beginning of treatment, compete healing of the epithelial defect in the RE was obtained, while the severity of the SPK in the LE markedly improved; in parallel, conjunctival hyperemia disappeared in BE. The treatment was continued over the course of 3 months with good tolerability and neither signs of recurrence of the epithelial defect nor other complications were noted.

Conclusions and Importance

Allogeneic serum eye drops obtained from the mother are effective in treating pediatric NK owing to CCA. This treatment may represent a readily available and inexpensive option when topical nerve growth factor is unavailable or corneal neurotization is not feasible.

Autologous versus allogeneic versus umbilical cord sera for the treatment of severe dry eye disease: a double-blind randomized clinical trial

PURPOSE

To measure the effects of Autologous serum (AS), Allogeneic Serum (HS) and Umbilical Cord serum (CS) eye drops in severe dry eye disease (DES), as well as to characterize and quantify several molecules in the three sera (albumin, fibronectin; Vitamin A and E; IgG, IgA and IgM; Transforming growth factor β; Epithelial growth factor).

METHODS

Randomized, double-blind, single-centre, three-arm (AS, HS and CS) clinical trial. Sixty-three subjects were included with severe DES, 21 in each arm of the study. Visual acuity, Schirmer test, Breakup time (BUT), lissamine green, fluorescein staining measurements and a questionnaire were performed prior to treatment, and after one-month and three-month follow-up.

RESULTS

There was a significant main effect of time on visual acuities, Schirmer and BUT tests and fluorescein and lissamine green staining measurements and questionnaire scores (p = 0.015, p = 0.002, p < 0.001, p < 0.001, p = 0.031 and p < 0.001, respectively), although there was no significant interaction between time and serum type, nor between serum type and the test performed. Regarding the concentration of molecules, in our study AS contained significantly higher concentrations of IgA, IgG and fibronectin whereas HS contained significantly higher concentration of IgM, vitamins A and E, TGF and albumin. Contrary to previous reports, CS did not show higher concentration of any of the molecules analysed.

CONCLUSIONS AND RELEVANCE

The three sera were effective in the treatment of severe DES. CS did not contain a higher proportion of molecules compared to AS/HS. More research is needed to assess the effect of AS in patients with DES and autoimmune diseases.

Transregional autologous serum eye drop provision by a large German Red Cross Blood Donation Service

BACKGROUND

The Blood Donation Service West serves North Rhine-Westphalia (NRW), Rhineland-Palatinate (RP), and Saarland, an area of 56,500 km². In addition to routine red blood cell concentrates, plasma, and platelets, special products are provided. Since 2014, this has included autologous serum eye drops (ASED) for topical use in patients suffering from different illnesses accompanied by dry eye disease.

METHODS

A volume of 250-525 mL of patient blood was collected into an anticoagulant-free blood bag. Laboratory testing included Hepatitis B/C-, HIV 1/2-, and Lues-serology. Coagulation and centrifugation were followed by leukoreduction. Single-use vials were obtained by filling mini-bag systems using a sterile tube welder. Storage at ≤-20 °C enabled a shelf-life of up to 6 months and 30 days at 4 °C after thawing for shipment.

RESULTS

Contracts were closed with 15 ophthalmology clinics and medical practices in NRW and RP to supply patients with ASED. The patient pool increased from 19 in 2014 to 46 in 2020, with an average age of 43-55 years. Overall, blood collections almost tripled from 31 to 100 per year, increasing the stock of deliverable single-use vials from 3328 to 13,358. Delivery in a liquid state allowed engagement of 44 pharmacies located in the patient neighborhoods for continuous supply.

CONCLUSION

Manufacturing in a closed bag system allowed integration into blood bank operations. However, cost-coverage by health insurance remained a case-by-case decision. Allogeneic application as 'just-another-blood-product' could be an aspiration. Yet, conclusive data from large clinical trials are needed for licensed provision in Germany.

Treatment of persistent epithelial defects with single-dose autologous serum eye drops

PURPOSE

We aimed to investigate the efficacy and safety of single-dose autologous serum eye drops (ASEDs) for treatment of persistent corneal epithelial defects (PEDs).

METHODS

About 34 eyes of 26 patients treated from March 2016 to May 2020 with a single dose of ASEDs for PEDs that did not respond to conventional treatment were retrospectively evaluated. Patient demographics, predisposing factors, size, and duration of the PED, duration of treatment, and dosage of ASEDs, PED healing time, success rate of the ASED treatment, and follow-up time after the onset of ASED treatment were recorded. Autologous serum eye drops (20%) were prepared by diluting the serum with preservative-free artificial tears in single-dose vials. Vials were stored at -20°C and used daily after dissolving.

RESULTS

The mean patient age was 47.0 ± 18.5 years, and 13 (50%) of the patients were male. The most common indication for ASEDs was PED after keratoplasty. The mean duration of ASED treatment was 8.5 ± 6.3 months, and mean follow-up time was 22.8 ± 12.2 months. Autologous serum eye drop treatment was effective in 25 (73.5%) eyes and partially effective in 5 (14.7%) eyes. None of the eyes displayed complications related to the treatment.

CONCLUSION

In patients with PED for whom conservative treatment is insufficient, ASEDs prepared by dilution with preservative-free artificial tears in single-dose vials and administered based on the daily use principle appear to be effective and safe.

[Standardized management of platelet derivatives for tissue regeneration research and applications]

Objective

To summary the standardized management in research and applications of platelet derivatives for tissue regeneration.

Methods

The related literature about bottlenecks and standardized management of platelet derivatives in recent years was reviewed and analyzed.

Results

Although the platelet derivatives are increasingly used to accelerate the regenerative processes of injured joint, skin, nerve, ligament/tendon, and alveolar bone, etc., the large variation in preparation methods, diverse nomenclature, incomplete reporting system, and lack of quantitative and standardized management of the preparation process have caused uncertainty and incomparability of research and application results. In recent years, there has been a trend towards standardized research and management of platelet derivatives.

Conclusion

The implementation of standardized research and quality management will contribute to promote the research and application of platelet derivatives in the field of tissue regeneration.

Smart nano-micro platforms for ophthalmological applications: The state-of-the-art and future perspectives

Smart nano-micro platforms have been extensively applied for diverse biomedical applications, mostly focusing on cancer therapy. In comparison with conventional nanotechnology, the smart nano-micro matrix can exhibit specific response to exogenous or endogenous triggers, and thus can achieve multiple functions e.g. site-specific drug delivery, bio-imaging and detection of bio-molecules. These intriguing techniques have expanded into ophthalmology in recent years, yet few works have been summarized in this field. In this work, we provide the state-of-the-art of diverse nano-micro platforms based on both the conventional materials (e.g. natural or synthetic polymers, lipid nanomaterials, metal and metal oxide nanoparticles) and emerging nanomaterials (e.g. up-conversion nanoparticles, quantum dots and carbon materials) in ophthalmology, with some smart nano/micro platformers highlighted. The common ocular diseases studied in the field of nano-micro systems are firstly introduced, and their therapeutic method and the related drawback in clinic treatment are presented. The recent progress of different materials for diverse ocular applications is then demonstrated, with the representative nano- and micro-systems highlighted in detail. At last, an in-depth discussion on the clinical translation challenges faced in this field and the future direction are provided. This review would allow the researchers to design more smart nanomedicines in a more rational manner for specific ophthalmology applications.

Fingerprick Autologous Blood in the Treatment of Severe Dry Eyes and Ocular Surface Disease

PURPOSE

To evaluate the efficacy of autologous blood eye drops in patients diagnosed with severe ocular surface disease and dry eye who were unresponsive to conventional therapy and who would otherwise be considered for autologous serum eye drops.

METHODS

A total of 38 eyes of 19 patients (15 women and 4 men) with ocular surface disease and severe dry eye refractory to conventional treatment were treated with fingerprick autologous blood 4 times daily for 6 months. Follow-up visits occurred at 1-, 3-, and 6-month intervals. At each visit, visual acuity, Oxford Grading Scheme score, tear film break-up time, Schirmer test, and ocular surface disease index were measured.

RESULTS

There was a significant improvement in the ocular surface staining score at all time gates. The mean score at presentation was 2.13, and this improved to 1.50 at 1 month (P < 0.001), 1.29 at 3 months (P < 0.01), and 1.42 at 6 months (P < 0.01). There was an improvement in tear film break-up time from 4.75 seconds at baseline to 6.79 seconds at 3 months (P < 0.01) and 7.0 seconds at 6 months (P < 0.001). An improvement in the Schirmer test was only found at 6 months with an improvement from 3.67 mm to 13.33 mm (P < 0.05). There was no statistical change in visual acuity at any time gate or ocular surface disease index score, although 83% of patients reported an improvement in their symptoms at 6 months. There were no adverse events reported.

CONCLUSIONS

Fingerprick autologous blood is an effective, readily accessible, and safe therapy for the treatment of recalcitrant cases of severe ocular surface disease and dry eye unresponsive to conventional therapy.

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.

Effect of Autologous Serum Eyedrops on Ocular Surface Disease Caused by Preserved Glaucoma Eyedrops

Autologous serum eyedrops (ASE) are effective in treating various ocular surface diseases, including damages induced by long-term use of preserved glaucoma eyedrops. However, there has been no study on whether ASE is effective without stopping the causative eyedrops. This retrospective observational study included 55 patients with ocular-surface diseases caused by long-term use of preserved glaucoma eyedrops: 18 patients who used ASEs for 2 months without discontinuing the use of glaucoma eyedrops (Group 1), 22 patients who used ASEs for 2 months, discontinuing the use of glaucoma eyedrops for the first month (Group 2) and 15 patients who used non-preservative artificial tears for 2 months, discontinuing the use of glaucoma eyedrops for the first month (Group 3). There were no intergroup differences in the baseline values of the Schirmer I test results, tear breakup time (TBUT), ocular surface staining (OSS) score, loss of the meibomian gland, meibum quality and ocular-surface disease index (OSDI). Group 1 showed significant differences in TBUT, OSS score and OSDI at 2 months when compared to the baseline values before treatment, while Group 2 showed significant differences in those values at both 1 and 2 months. There were no differences in any of the parameters at baseline, 1 month or 2 months in Group 3. Our result suggested that ASE is effective for treating ocular surface diseases caused by glaucoma eyedrops containing preservatives and its effects can be expected without interruption of glaucoma eyedrop treatment.

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.

Development and Optimization of Freeze-Dried Eye Drops Derived From Plasma Rich in Growth Factors Technology

Purpose

To investigate whether plasma rich in growth factors (PRGF) eye drops maintain their biological potential after a freeze drying process. The addition of a lyoprotectant like trehalose was also evaluated.

Methods

Blood from three healthy donors was collected to obtain eye drops by PRGF technology. The resultant eye drops were divided in four groups: PRGF, freeze-dried PRGF (PRGF lyo), and PRGF lyophilized mixed with 2,5% trehalose (PRGF lyo+2.5T) or 5% trehalose (PRGF lyof+5T). Chemical and biological characteristics were evaluated. Photorefractive keratectomy was performed on C57BL/6 mice which were divided in three treatment groups: control, PRGF, and PRGF lyo. Corneal wound healing and haze formation were evaluated macroscopically. Eyes were collected at 1, 2, 3, and 7 days after surgery, and were processed for histologic studies.

Results

The pH values of PRGF samples increased significantly after the lyophilization process. Osmolarity levels increased significantly in PRGF samples mixed with trehalose in comparison with PRGF samples without protectants. The freeze drying process maintained growth factors levels as well as the biological properties of PRGF eye drops even without the use of lyoprotectants. PRGF lyo treatment significantly decreased the re-epithelialization time and haze formation in photorefractive keratectomy-treated corneas regarding PRGF and control groups. Furthermore, the PRGF lyo group significantly decreased the number of smooth muscle actin-positive cells in comparison with the control group at each time of the study and at days 2 and 3 in the PRGF group.

Conclusions

The freeze drying process preserves the protein and growth factor content as well as the biological properties of PRGF eye drops, even without the use of protectants. Freeze-dried PRGF eye drops accelerate corneal tissue regeneration after photorefractive keratectomy in comparison with the control group.

Translational Relevance

Our study shows the feasibility to preserve the biological capability of PRGF eye drops as freeze-dried formulation, avoiding the addition of protectants.

Characteristics of Platelet Lysate Compared to Autologous and Allogeneic Serum Eye Drops

Purpose

Platelet lysate produced from platelet apheresis components has been proposed as an alternative to serum eye drops in the treatment of ocular surface disease. This study compared the effects of platelet lysate and serum on growth factor, cytokine and nanoparticle concentrations, and corneal epithelial cell proliferation.

Methods

The concentration of growth factors, cytokines, and nanoparticles in platelet lysates manufactured from either fresh or expired platelet apheresis concentrations collected with Trima or Haemonetics technology was characterized and compared with those of allogeneic, autologous, and fetal calf serum. The ability to promote corneal epithelial cell proliferation and wound healing was tested in vitro.

Results

Platelet lysate enriched the amount of transforming growth factor β1, platelet-derived growth factor –AB and –BB, fibroblast growth factor, and epidermal growth factor compared with the two sera groups. The concentrations of insulin-like growth factor 1, hepatocyte growth factor, and fibronectin were significantly lower than in sera. There were no differences in nanoparticle concentrations. There was no significant difference in corneal epithelial cell proliferation. Platelet lysates were comparable to fetal calf serum in accelerating corneal epithelial wound healing in vitro.

Conclusions

Fresh and expired platelet lysates from the Trima and Haemonetics systems had higher growth factor concentrations than sera. The ability of platelet lysates to promote corneal epithelial cell proliferation and wound healing was equivalent to sera.

Translational Relevance

Platelet lysates may serve as an efficient and reliable source of human growth factors for the treatment of ocular surface diseases.

An Environmental Control Experiment for Contamination of the Production and Storage of 20% Autologous Serum Eye Drops

Purpose: To investigate the sterility of autologous serum eye drops used for ocular surface diseases. Methods: A total of 100 patients were enrolled. The serum was prepared as follows: 20% serum (20% S), 20% serum with dexamethasone (0.02 mg/ml) (20% S + Dex), and 20% serum with levofloxacin (0.1 mg/ml) (20% S + Lev). Serum samples were collected for normal microbial cultivation at 1, 3, 5, 7, 10, 14, 21, and 28 days. The last samples were also assessed on the 28th day by airtight microbial cultivation. Results: A total of 2400 samples were cultured, and the bacterial contamination rates of 20% S, 20% S+ Dex, and 20% S + Lev group were 4.75%, 3.38%, and 0.88%, respectively, for normal microbial cultivation. There was no significant difference in bacterial contamination among the three groups with times (P = .502). Bacterial contamination of the 20% S + Lev group showed a significant difference in comparison with the 20% S or 20% S + Dex group (P < .05) in two culture methods; however, no significant difference was found between the 20% S and 20% S + Dex group (P = .208). There were two samples positive for fungi in the 20% S and 20% S + Dex group and three samples in the 20% S + Lev group in normal cultivation during 28 days. None of the samples was positive with fungi in airtight cultivation on the 28th day. There was also less bacterial contamination in airtight cultivation than in normal cultivation for the three groups on the 28th day. Conclusions: Our study shows that 20% autologous serum drops can be safely prepared and stored at 4°C in an open system under a strict protocol for at least 28 days, and antimicrobial agents could reduce the risk of contamination.

Serum eye drops for the treatment of ocular surface diseases: a systematic review and meta-analysis

BACKGROUND

The use of blood-derived eye drops for topical treatment of ocular surface diseases has progressively increased in recent years.

MATERIALS AND METHODS

To evaluate the use of serum eye drops in ocular surface disorders, we performed a systematic search of the literature.

RESULTS

In this systematic review, we included 19 randomised controlled trials (RCTs) investigating the use of serum eye drops in 729 patients compared to controls. For the quantitative synthesis, we included only 10 RCTs conducted in patients with dry eye syndrome comparing autologous serum to artificial tears. At 2-6 weeks, no clear between-group differences in Schirmer test (MD 1.05; 95% CI: -0.17-2.26) and in fluorescein staining (MD -0.61; 95% CI: -1.50-0.28) were found (very low-quality evidence, down-graded for inconsistency, serious risk of biases, and serious imprecision). Slightly higher increase in tear film break-up time (TBUT) scores in autologous serum compared to control (MD 2.68; 95% CI: 1.33-4.03), and greater decrease in ocular surface disease index (OSDI) in autologous serum compared to control (MD -11.17; 95% CI: -16.58 - -5.77) were found (low quality evidence, down-graded for serious risk of bias, and for inconsistency). For the Schirmer test, fluorescein staining and TBUT, data were also available at additional follow-up timing (2-12 months): no clear between-group differences were found, and the quality of the evidence was graded as low/very-low.

CONCLUSIONS

In patients with dry eye syndrome, it is unclear whether or not the use of autologous serum compared to artificial tears increases Schirmer test and fluorescein staining scores at short-term and medium-/long-term follow up. Some benefit at short-term follow up for the outcome of TBUT and OSDI was observed, but the quality of the evidence was low.

Blood derived treatment from two allogeneic sources for severe dry eye associated to keratopathy: a multicentre randomised cross over clinical trial

AIM

To compare the efficacy of cord blood and peripheral adult donor blood serum eyedrops, controlled for growth factor content, in the treatment of severe dry eye diseases (DED) resistant to conventional therapy.

METHODS

This was a multicentre randomised, double-masked, cross-over clinical trial. Sixty patients diagnosed as severe DED, associated to persistent corneal epithelial defects were randomised and equally assigned to group A (treated with cord blood serum (CBS)) or group B (treated with PBS), eyedrops administered eight times/day for 1 month. Primary outcome was the pretreatment and post-treatment change in corneal fluorescein staining. Secondary outcomes included the pretreatment and post-treatment change in Ocular Surface Disease Index (OSDI) questionnaire and Visual Analogue Score (VAS) of subjective symptoms, Schirmer I test, tear break-up time and conjunctival staining. Patients with relapse in signs or symptoms after further 2 months switched to the remaining group for one additional month. Data were statistically analysed (p<0.05).

RESULTS

Corneal staining was more significantly reduced after the CBS treatment, both VAS and OSDI score reduction was observed in both groups, but group A reported significantly less grittiness and pain. Nineteen patients shifted in the crossover period, the within individual comparison confirmed a better recovery in the CBS treatment period. Reduction in epithelial damage was positively associated with epidermal growth factor, transforming growth factorα and platelet-derived growth factor content. Levels of interleukins (IL-13) were positively associated with symptom decrease.

CONCLUSIONS

Overall, DED signs improved after both CBS and PBS treatments, with potential advantages of CBS for subjective symptoms and corneal damage reduction.

CLINICAL TRIAL REGISTRATION

NCT03064984.

Autologous platelet-rich plasma for healing chronic venous leg ulcers: Clinical efficacy and potential mechanisms

The overall quality of evidence of autologous platelet-rich plasma (PRP) for treating chronic wounds remains low. While further well-designed clinical studies are clearly required to convincingly demonstrate the efficacy of autologous PRP in improved healing of venous leg ulcers (VLUs) and other chronic wounds, there is also an increasing need to better define the underlying mechanisms of action and whether positive outcomes can be predicted based on the analysis of PRP. This brief review will discuss the current understanding of autologous PRP in VLUs and whether molecular evaluation of PRP at the time of collection could potentially be informative to clinical outcomes. Benefits of the autologous PRP treatment strategy include that PRP is easily accessible and is relatively inexpensive and safe. Better understanding of the mechanisms involved could improve treatment, enable supplementation, and/or lead to gains in product development. Analysis of PRP could also add value to future clinical trials on efficacy and potentially personalised treatment regimens.

Reflections on Dry Eye Syndrome Treatment: Therapeutic Role of Blood Products

Dry eye syndrome (DES) is a multifactorial, frequent, pathology characterized by deficient tear production or increased evaporation of tears and associated with ocular surface alteration and inflammation. It mostly affects, but not exclusively, older individuals and leads to varying degrees of discomfort and decreased quality of life. Although the typical treatments of DES rely on using artificial tears, polyunsaturated fatty acids, integrin antagonists, anti-inflammatory agents, or on performing punctal occlusion, recently, standardized blood-derived serum eye drops (SED) are generating much interest as a new physiological treatment option. The scientific rationale in using SED for treating or releasing the symptoms of DES is thought to lie in its composition in multiple factors that resembles that of tears and contributes to the healing and protection of the ocular surface. This manuscript seeks to provide relevant background information on the management of DES, and on the increasing role that various types of SED or platelet lysates, from autologous or allogeneic origins, are playing in the improved therapeutic management of this pathology. The increasing role played by blood establishments in producing better-standardized SED is also addressed.

Leukocyte depletion does not affect the in vitro healing ability of platelet rich plasma

The clinical use of platelet-rich plasma (PRP) containing or deprived of leukocytes remains a subject of debate and a controversial issue. It is not yet clear whether leukocyte content has a positive or negative effect on tissue healing processes. Several studies, conducted mainly in the orthopedic field, support the use of leukocyte-poor (LP) PRP, whereas other studies have not identified any significant differences between the use of LP and leukocyte-rich PRP. In the present study, the role of leukocytes contained in PRP was assessed to verify their in vitro effect on fibroblasts and endothelial cells, which have a leading role in the biological processes associated with wound healing (including angiogenesis and matrix remodeling). The original sample of PRP was divided into two aliquots, one of which remained unaltered, while the other was deprived of leukocytes. The two aliquots were used in in vitro tests in order to verify the effects of leukocytes on proliferation, wound healing and tube formation, and in molecular analyses of growth factor and enzyme content. The present results highlighted a substantial overlap between the two formulations. This may be explained by similar levels of growth factors (vascular endothelial growth factor, thrombospondin-1, interferon-γ, platelet-derived growth factor-BB, -AA and -B, tumor growth factor-β1, fibroblast growth factor 7 and tumor necrosis factor-α) and enzymes (gelatinases and plasminogen activators) in the two formulations. These results support the hypothesis that the ability of the PRP to affect the in vitro biological response of endothelial cells and fibroblasts does not rely on the presence of leukocytes.

Regenerative Therapies in Dry Eye Disease: From Growth Factors to Cell Therapy

Dry eye syndrome is a complex and insidious pathology with a high level of prevalence among the human population and with a consequently high impact on quality of life and economic cost. Currently, its treatment is symptomatic, mainly based on the control of lubrication and inflammation, with significant limitations. Therefore, the latest research is focused on the development of new biological strategies, with the aim of regenerating affected tissues, or at least restricting the progression of the disease, reducing scar tissue, and maintaining corneal transparency. Therapies range from growth factors and cytokines to the use of different cell sources, in particular mesenchymal stem cells, due to their multipotentiality, trophic, and immunomodulatory properties. We will review the state of the art and the latest advances and results of these promising treatments in this pathology.

Proinflammatory and Anabolic Gene Expression Effects of Platelet-Rich Gel Supernatants on Equine Synovial Membrane Explants Challenged with Lipopolysaccharide

Platelet-rich plasma (PRP) preparations are used in horses with osteoarthritis (OA). However, some controversies remain regarding the ideal concentration of platelets and leukocytes to produce an adequate anti-inflammatory and anabolic response in the synovial membrane. The aims of this study were to study the influence of leukoconcentrated platelet-rich gel (Lc-PRG) and leukoreduced platelet-rich gel (Lr-PRG) supernatants on the quantitative expression of some proinflammatory and anabolic genes in equine synovial membrane explants (SMEs) challenged with lipopolysaccharide (LPS). SMEs from six horses were cultured over 96 h. Then, SMEs were harvested for RNA extraction and quantitative gene expression analysis by RT-qPCR for nuclear factor kappa B (NFκB), matrix metalloproteinase 13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS-4), collagen type I alpha 1 (COL1A1), collagen type II alpha 1 (COL2A1), and cartilage oligomeric matrix protein (COMP). The 25% and 50% Lc-PRG supernatants led to downregulation of NFκB, MMP-13, ADAMTS-4, COL1A1, COL2A1, and COMP in SMEs. Lr-PRG supernatants (particularly at the 50% concentration) induced downregulation of NFκB, MMP-13, ADAMTS-4, and COL1A1 and upregulation of COL2A1 and COMP. Lr-PRG supernatants should be used for the treatment of inflammatory arthropathies in horses because they have anti-inflammatory and anabolic effects in the synovial membrane.

Safety of Cultivated Limbal Epithelial Stem Cell Transplantation for Human Corneal Regeneration

Ex vivo cultivated limbal stem cell transplantation is a promising technique for the treatment of limbal stem cell deficiency. While the results of the clinical trials have been extensively reported since the introduction of the technique in 1997, little has been reported regarding the potential health risks associated with production processes and transplantation techniques. Culture procedures require the use of animal and/or human-derived products, which carry the potential of introducing toxic or infectious agents through contamination with known or unknown additives. Protocols vary widely, and the risks depend on the local institutional methods. Good manufacturing practice and xeno-free culture protocols could reduce potential health risks but are not yet a common practice worldwide. In this review, we focus on the safety of both autologous- and allogeneic-cultivated limbal stem cell transplantation, with respect to culture processes, surgical approaches, and postoperative strategies.