Approved for distribution to Healthcare Professionals only

CoEnzyme Q10: New approach in the treatment of corneal damage and glaucomaProceedings of the Symposium held on October 9th, 2017 at the ESCRS Congress, Lisbon, Portugal

VIS

U/E

U/C

QN

/0007

FACULTYDr. Sajjad AhmadDr. Pasquale AragonaDr. José Manuel Benitez del Castillo SánchezDr. Francesca Cordeiro

the eye health company

2 3Approved for distribution to Healthcare Professionals only Approved for distribution to Healthcare Professionals only

Dry eye is a multifactorial disease of the tears and ocular surface resulting in symptoms of discomfort, visual disturbance and tear film instability, with potential damage to the ocular surface. It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface.1 Dry eye can be acute or chronic, it can be caused by either exogenous factors such as acute post-surgery trauma or endogenous triggers such as hormonal imbalance or autoimmune diseases.2 Symptom relief is normally achieved by lubrication of the ocular surface, while other strategies target the underlying inflammation and contribute to corneal wound healing. A recent approach is the use of cross-linked hyaluronic acid to ensure a maximum residence time on the ocular surface, in combination with Coenzyme Q10 (CoQ10), the latter regulating mitochondrial apoptosis by acting as antioxidant and support of energy production.

Glaucoma is one of the leading causes of irreversible blindness worldwide. It is recognized as a progressive neurodegenerative disorder, affecting the retinal ganglion cells (RGCs) and their axons. The death

of RGCs ultimately leads to the loss of visual field. Recent evidence indicates that there is a link between the pathogenesis of glaucoma and mitochondrial dysfunction: As RGC axons are rich in mitochondria, an alteration of the functional status of these mitochondria will influence RGC survival and thus their functional contribution to the vision process. An endogenous molecule maintaining the mitochondrial function is CoQ10, potentially offering a complementary approach to IOP lowering therapy in glaucoma.

The newest findings on CoQ10 for both indications were presented during a symposium at the 2017 Meeting of the European Society of Cataract & Refractive Surgeons (ESCRS) in Lisbon, Portugal, chaired by Professor Leopold Schmetterer, Professor of Ophthalmology at the Singapore Eye Research Institute and Nanyang Technological University in Singapore.

● Dry eye is a multifactorial disease of the tears and ocular surface resulting in symptoms of discomfort, visual disturbance and tear film instability. It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface.

● Corneal nerves appear to be very important in tear production and a decreased amount of such nerves after ocular surgery such as LASIK or cataract can be detected. Such interventions can lead to a vicious cycle of ocular surface disease (OSD). Existing hypoesthesia causes a reduced blink rate and damage to conjunctival goblet cells leading to instability of the ocular surface. In this environment inflammatory processes kick off, acting on the lacrimal glands by initiating a cycle of its hypo- or hyperstimulation and neurogenic inflammation.

● CoEnzyme Q10 (CoQ10) has two important functions. It is a key component for the generation of ATP in the mitochondria and it has anti-oxidant effects to neutralize reactive oxidant species (ROS), thereby inhibiting cell apoptosis. It also exerts an anti-apoptotic activity associated with inhibiting the opening of transition pores (PTP).

● While systemic use of CoQ10 has been shown to have some effect on diseases of the central nervous system, there is also significant pre-clinical evidence for a protective activity of CoQ10 in several ocular cell types. Currently, clinical evidence is becoming available to support the beneficial role of CoQ10 in several ophthalmic diseases.

● A widely used lubricant is hyaluronic acid (HA). As a natural glucosoaminoglycane constituent of the extracellular matrix and a non-Newtonian fluid it shares some similarities with natural tears.

● To allow an eye drop to achieve an increased residence time on the ocular surface with lower concentrations, a formulation with cross-linked HA (XLHA) can be used. Its very high molecular weight and size results in an increased resistance to hyaluronidase degradation.

● A new combination of XLHA and CoQ10 is very useful in the treatment of dry eye induced ocular surface damage. While XLHA is a well-tolerated, high molecular weight HA showing all the characteristics of HA, CoQ10 acts as a potent anti- oxidant.

● An addition of CoQ10 to the preoperative and postoperative standard of care, may accelerate full patient recovery and decrease sequelae such as dry eye and neuropathic pain. The beneficial effect of CoQ10 should be further investigated by conducting well-defined longer-term clinical trials to help better understand the mechanism of action of this promising new approach.

● Glaucoma is one of the leading causes of irreversible blindness worldwide. It is currently recognized as a progressive neurodegenerative disorder, affecting the retinal ganglion cells (RGCs) and their axons. The death of RGCs ultimately leads to the loss of visual field.

● There is a clear unmet need in glaucoma. When looking at landmark glaucoma trials such as OHTS, EMGT and CNTGS, one will find that successful IOP reduction does not necessarily prevent loss of vision and this is where the concept of neuroprotection comes in.

● Recent evidence indicates there is a link between the pathogenesis of glaucoma and mitochondrial dysfunction: As RGC axons are rich in mitochondria, an alteration of the functional status of these mitochondria will influence RGC survival and thus their functional contribution to the vision process.

● An endogenous molecule maintaining the mitochondrial function is Coenzyme Q10 (CoQ10), potentially offering a complementary approach to IOP lowering therapy in glaucoma

● CoQ10 targets mitochondria. It appears to reach the back of the eye and this suggests potential utility as neuroprotective therapy in glaucoma through preventing RGC apoptosis and functional loss. CoQ10 may also counteract reperfusion damage.

● In vitro and in vivo data shows that application of CoQ10 prior to exposure to apoptotic stimuli, reduces apoptosis by a direct inhibition of mitochondrial depolarization.

● In clinical study CoQ10 has been shown to have an effect on electrophysiological parameters such as VEP and PERG in patients with glaucoma.

● Further proof-of-concept studies with strong endpoints are needed to determine the effect of CoQ10 on visual field function.

SummaryIntroduction

4 5Approved for distribution to Healthcare Professionals only Approved for distribution to Healthcare Professionals only

OCULAR SURFACECoEnzyme Q10 and mitochondrial function: what is their role in ocular diseases?

Dr. Sajjad Ahmad, Consultant Ophthamic Surgeon, Moorfields Eye Hospital; Senior Clinical Lecturer,UCL Institute of Ophthamology, London, UK

“Before looking at its clinical application, it is important to initially understand the basic science of CoQ10 such as its characteristics and functions in the cell”, Dr. Sajjad Ahmad, Consultant Ophthamic Surgeon at Moorfields Eye Hospital in London, introduced the topic to the audience.

Coenzyme Q10 consists of a quinone and 10 isoprenyl subunits. It is present in most bacteria and mainly in the mitochondria of animal cells. It is endogenously produced mainly by the liver and thus nutritionally non-essential, although approximately 25% of CoQ10 is obtained via dietary sources. CoQ10 levels decline with age.3

CoQ10 has two important functions. It is a key component for the generation of ATP in the mitochondria and it has anti-oxidant effects to neutralize reactive oxidant species (ROS) indirectly inhibiting cell apoptosis. In the inner membrane of the mitochondria a proton (H+) gradient is produced via an electron transport chain, which drives ADP phosphorylation to ATP. ROS are produced by exogenous sources such as heat or radiation, or endogenous sources such as the mitochondria. Unchecked, ROS results in apoptosis, senescence and neoplasia. ROS are oxygen containing highly active free radicals as a result of having an unpaired electron. CoQ10 can neutralize ROS by electron acceptance. (Graphic 1)

Graphic 1: CoQ10 mechanism of electron carriage in mitochondria

A group of Italian researchers was also able to show an additional function of CoQ10 within mitochondria: The permeability transition pores (PTP) are mitochondrial channels. When opened the mitochondrial membrane potential collapses and this depolarization leads to apoptosis. CoQ10 exerts an anti-apoptotic activity associated with inhibition of PTP opening.4

CoQ10 deficiencies can be manifest as 5 clinical sub-types, including CNS, muscle and renal involvement. According to literature, the response to CoQ10 supplementation is variable.5

“In terms of clinical application, the use of orally administered CoQ10 was first reported in systemic diseases, where several clinical trials have been published”, said Dr. Ahmad. Two meta-analyses show an improved ejection fraction in heart failure patients.6,7 There is also evidence for CoQ10 efficacy in neurological diseases. Several trials have shown neuroprotective effects in Alzheimer’s disease, Parkinson’s disease and Friedreich’s ataxia.8

In recent years, the effect of CoQ10 on different tissues of the eye has also been studied. This includes in vitro and animal data. In the cornea, an anti-apoptotic effect of CoQ10 in ethanol treated corneal fibroblasts has been shown9.There is also in vitro and in vivo evidence for a protective effect of CoQ10 in UVB radiated corneal epithelial cells.10 A reduced oxidative damage was observed in CoQ10 treated lens epithelial cells exposed to hydrogen peroxide.11 In the back of the eye, CoQ10 has shown to prevent apoptosis in retinal ganglion cells and retinal pigment epithelial cells exposed in vitro to radiation, hypoxia and growth factor deprivation. Furthermore topical CoQ10 had an anti- apoptotic effect on retinal ganglion cells in a mouse model of induced retinal damage.12 CoQ10 exposure was shown to inhibit oxidative stress and increase mitochondrial mass in hydrogen peroxide treated optic nerve head cells and astrocytes.13 It also reduced oxidative stress induced mitochondrial alterations as a result of transient ischemia in mouse model.14

As a corneal and ocular surface disease specialist, Dr. Ahmad noted that: “Clinical data has now also become available on the efficacy of CoQ10 in two challenging corneal endothelial diseases. Authors of a case series reported adjuvant use of CoQ10 in corneal ulcers, where it enhanced corneal healing, while another research group found it to be an effective supportive measure in recovery of the cornea in patients suffering from Fuchs endothelial corneal dystrophy.” 15,16

Dr Ahmad summarized that “CoQ10 is important in the production of ATP, as an anti-oxidant for ROS and a direct anti-apoptotic agent. While systemic use of CoQ10 has been shown to have some effect on diseases of the central nervous system, there is also significant pre-clinical evidence for a protective activity of CoQ10 in several ocular cell types. Currently, clinical evidence is becoming available to support the beneficial role of CoQ10 in several ophthalmic diseases.”

Cross-linked HA and CoQ10: their impact in dry eye disease and ocular surface damage

Dr. Pasquale Aragona, Full Professor and Chairman of Ophthalmology, Eye Clinic Department of Biomedical Sciences, University of Messina, Messina, Italy

Dr. Aragona presented an overview of the updated evidence based definition and contemporary classification system for dry eye disease (DED), recently published by the TFOS DEWS II Definition and Classification Subcommittee. The new publication integrates the former definition that, dry eye is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface and is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface. Additionally, it now also recognizes the multifactorial nature of dry eye as a disease, where loss of homeostasis of the tear film is the central pathophysiological concept. Ocular symptoms, as a broader term that encompasses reports of discomfort or visual disturbance, feature in the definition and the key etiologies of tear film instability, hyperosmolarity, and ocular surface inflammation and damage were determined to be important for inclusion. In the light of new data, neurosensory abnormalities were also included in the definition for the first time. A decision tree for diagnosis and management of dry eye disease is available to help guide clinical management and research, in addition to clinical assessment and judgment (Graphic 2).

Graphic 2: TFOS DEWS II Management of DED

Graphic presented with permission from DEWS.

In this classification of DED, recent evidence supports a scheme based on the pathophysiology where aqueous deficient and evaporative dry eye exist as a continuum, so that elements of each are considered in diagnosis and management. The clinical decision algorithm begins with the assessment of symptoms and is followed by review for signs of ocular surface disease. Central to the scheme is a positive diagnosis of DED with signs and symptoms, and this is directed towards management aiming to restore homeostasis.

“DED can be differentiated from other ocular surface disease by use of triaging questions and ancillary testing. It is to this DED group that diagnostic subtyping, and conventional dry eye management strategies, apply. Symptomatic patients without demonstrable clinical signs do not fall into the DED group, but are differentiated into pre-clinical dry eye or neuropathic pain (non-ocular surface disease). Conversely, asymptomatic patients, exhibiting signs are differentiated into patients with poor corneal sensitivity, or those with prodromal signs, who are at risk of developing manifest DED with time or provocation, for example following ophthalmic surgery. An etiological classification of DED is also presented, and highlights the two predominant and non-mutually exclusive categories; aqueous deficient dry eye (ADDE) and evaporative dry eye (EDE). While it is possible that ADDE can occur without obvious signs of EDE and vice versa, as DED progresses, it is increasingly likely that characteristics of both ADDE and EDE will become evident”, explained Dr. Aragona.

Endogenous factors such as hormonal imbalance or systemic diseases as well as exogenous factors including bacterial infections, use of medications and ophthalmic surgery can influence the tear film and initiate a vicious circle, if not compensated. The key mechanisms of DED are tear film instability, tear hyperosmolarity, apoptosis, nerve impairment and inflammation. It is important to keep all these factors in mind for a correct diagnosis and consecutive treatment with the goal to establish a stable tear film. From these facts, several principles for management of DED can be deduced.

The tear substitute used should be similar to natural tears. It should thus have non-Newtonian rheological properties, which means that its viscosity will be reduced by an increasing shear rate when blinking takes place. The substitute should help improve epithelial conditions, also by reducing inflammation through causing only minimal friction.

An ideal substance to satisfy these needs is hyaluronic acid (HA). It is a natural glucosoaminoglycane constituent of the extracellular matrix. It is also a non-Newtonian fluid and has been successfully used as tear substitute in preparations containing middle to long chain preparations of 500 kD or higher.17 HA increases the speed of repair mechanisms in the course of epithelial healing, as reported from an in vitro study using HA in the sub-epithelial region of rabbit cornea,

6 7Approved for distribution to Healthcare Professionals only Approved for distribution to Healthcare Professionals only

20 days after photorefractive keratectomy (PRK).18,19 HA has also been shown to improve migration of epithelial cells.20,21,22

The ocular surface expresses the hyaluronate receptor CD44: When CD44 is overexpressed in corneal and conjunctival cells - in the course of ocular surface damage - it promotes the interaction of the inflammatory marker ICAM-1 with cytoskeletal proteins. These findings suggest a role for hyaluronate in cell adhesion and motility.23,24

HA has also displayed healing properties in superficial punctate keratopathy. When the corneal epithelium was stained with fluorescein dye before and during treatment with HA eye drops, a discernible improvement was detected after 2 and 4 weeks of treatment.25

Longer term use of artificial tears containing HA has also been shown to promote epithelial healing in patients with more severe dry eye.26 In severe dry eye treatment the use of hypotonic HA formulations appear to be more effective. This was demonstrated during a 3 month study treating patients with Sjögren syndrome either hypotonic or isotonic artificial tears containing HA.27

“To allow an eye drop to achieve an increased residence time on the ocular surface with lower concentrations, a formulation with cross-linked HA (XLHA) can be used. Its very high molecular weight and size results in an increased resistance to hyaluronidase degradation”, knows Dr. Aragona. “This is why XLHA is for example used as a dermal filler and synovial fluid substitute.”

The way to produce XLHA is a relatively simple one. HA is immersed into water, then cross-linkers are added.28 Recent studies on XLHA have also shown it to unfold positive properties on the ocular surface. An improved tear film quality was detected in Sjogren’s patients29, as were reduced clinical signs in patients suffering from keratoconjunctivitis Sicca (KCS)30. Non-healing corneal ulcers were resolved when treated with XLHA.15

Another interesting new approach for treatment of OSD is the use of the lipid soluble CoQ10, also known as ubiquinone. As already described above, it plays a role in several cellular functions and is widely distributed in mitochondria, but also in microsomes, and the Golgi apparatus of cells. It is a key player in the oxidative metabolism, supporting biosynthesis of ATP in the mitochondria and, in its reduced form, acting as a lipid antioxidant.31

While the usefulness of CoQ10 in improving ocular surface damage has already been demonstrated in studies on UVB-induced corneal damage11 and corneal edema in Kearns-Sayre dystrophy17, a most recent study looked at the efficacy of eyedrops containing cross linked HA and CoQ10 in treating patients with mild to moderate dry eye. This randomized, single-masked, parallel-group, comparative study compared an unpreserved formulation of XLHA in combination

with CoQ10 (VisuXL®, VISUfarma, Rome, Italy) to an unpreserved 0.15% linear HA eyedrop (Ocuyal, Schalcon, Rome, Italy). To qualify for inclusion adult patients had to have a history of at least 3 months of dry eye symptoms categorized as moderate (stage 2-3 of DEWS classification). Patients with other ocular diseases, ocular surgery, contact lenses or topical treatments other than tear substitutes were excluded, as were patients with systemic diseases, hypersensitivity to the active substance or to excipients. After 1 week of saline use, patients were treated with either medication four times a day for 12 weeks. Evaluations carried out at baseline and after 15, 30 and 90 days were the OSDI (Ocular Surface Disease Index) assessment, BUT, ocular surface stain, corneal sensitivity, MGD assessment and in vivo confocal microscopy. Primary outcome measures were the OSDI as well as corneal and conjunctival fluorescein stain. In this comparable patient population the OSDI score improved significantly in both groups at day 30 and 90 compared to baseline and day 15. Additionally the score was significantly better for patients treated with XLHA at day 90 compared to those receiving HA. Conjunctival staining was significantly less in XLHA patients compared to HA at day 90, while corneal staining showed to be significantly less in XLHA patients compared to HA at day 30 and 90, and compared to baseline and day 15. These findings were also confirmed by in vivo confocal microscopy findings, showing an improvement in epithelium, keratocytes and stromal matrix. All these were reduced from day 30 in the XLHA group versus baseline and patients in the HA group over time.

Dr. Aragona concluded that “the formulation containing a combination of XLHA and CoQ10 is very useful in the treatment of dry eye induced ocular surface damage. While XLHA is a well-tolerated, high molecular weight HA showing all the characteristics of Hyaluronic acid, CoQ10 acts as a potent anti-oxidant”.32

Coenzyme Q10 and surgery: Its benefit in corneal regeneration

Dr. José Manuel Benitez del Castillo Sánchez, Professor of Ophthalmology and Chairman, Hospital Clinico San Carlos, Professor of Ophthalmology, University Complutense of Madrid, Spain

When discussing corneal surface disease, the consequences of corneal refractive and cataract surgery should also be kept in mind.

Dr. Benitez del Castillo reported from a study looking at tear secretion and corneal sensitivity after laser in situ keratomileusis (LASIK). There was a clear reduction of both 6 months after surgery. Tear secretion only returned to its preoperative values 9 months after the intervention.33 Corneal sensitivity recovery, as measured by non-contact aesthesiometry was not reached in many cases until more than 4 years after surgery. Recovery rates were even slower after hypermetropic LASIK.

Dr. Benitez del Castillo concluded that “corneal nerves appear to be very important in tear production and a decreased amount of such nerves after LASIK can be detected. Additionally LASIK can lead to a vicious cycle of OSD. Existing hypoesthesia causes a reduced blink rate and decreased presence of goblet cells. The tear film of the ocular surface becomes unstable. In this environment Interferon γ inhibits mucin generation and cytokines Interleukin 1,6 and 8 as well as TNF (tumor necrosis factor) alpha start kicking-off inflammatory processes, distorting sensitive information signalled to the brain. The brain in turn acts on the lacrimal gland initiating a cycle of its hypo- or hyperstimulation and neurogenic inflammation, prompting in neurotrophic keratopathy resulting in reduced tear clearance and production of Meibomian lipids and thus a tear film instability.” (Graphic 3)

Graphic 3: Post-LASIK ocular surface disease

Another surgical intervention potentially compromising the tear film is cataract extraction. It is usually performed in older people, in whom the ocular surface is already affected by age. Thus there are a lot of borderline patients with more DED, conjunctivochalasis and eyelid problems. They will also typically have a lower amount of nerves at the plexus with a decrease in corneal sensitivity and innervation.34

A study looking at the pathogenic factors in dry eye patients after cataract surgery found a decrease of the conjunctival epithelial cells and goblet cells by impression cytology at the lower conjunctiva covered by the lower lid. They concluded that DED after cataract surgery is related with drug toxicity.35 Even if the eye was satisfactorily covered by tear film before surgery, any irregularity and elevation related to incisional edema can also lead to tear film disturbances. Another group of researchers also detected changes in corneal sensitivity and tear physiology after phacoemulsification (Phaco). Using non-contact mechanical aesthesiometry on the central cornea they found a statistically significant decrease in corneal sensitivity until 3 months after surgery.36

“So how is DED triggered after phacoemulsification?”, explained Dr. Benitez del Castillo. The consequence is a non-satisfied patient. A study evaluating symptoms and their underlying causes after multifocal lens implantation, found that two major complaints were blurred vision and photic phenomena, caused by dry eye in 15% and 5% of patients, respectively.37 So there are a substantial number of pseudophakic patients complaining of dry eye. This is also the case in diabetic patients suffering from changes in tear film and tear secretion after Phaco.38 The administration of an artificial tear supplement after cataract surgery results in a reduction of ocular surface inflammation and dry eye signs and symptoms. This was assessed in 48 patients undergoing Phaco and receiving preservative free hydroxypropyl (HP)-guar eye drops in addition to the usual treatment scheme of corticosteroids. Inflammatory markers identified in flow cytometric analysis were reduced in patients receiving HP-guar eye drops.39

“As other mechanisms of action in dry eye treatment are being explored, the role of the mitochondria and effect of CoQ10 have increasingly been focused on. Mitochondria have a key role in the cell respiratory chain by producing energy using CoQ10. Following stress or damage, nerve, muscle and epithelium cells highly increase their O2 intake. During this activity CoQ10 increases the cell metabolism by exerting an anti-oxidant effect, producing energy and acting anti-apoptotic”, Dr. Benitez del Castillo continued. In vitro models have shown that the addition of CoQ10 increases the fraction of surviving cells after apoptosis induced by irradiation or ethanol.40,9

A group of Italian researchers was able to show that use of topical ubiquinone Q10 and vitamin E prevents keratocyte apoptosis after photorefractive keratectomy

8 9Approved for distribution to Healthcare Professionals only Approved for distribution to Healthcare Professionals only

(PRK) in rabbits. During 3 days before surgery, each right eye received CoQ10 0.2% + vitamin E 0.04% eye drops twice a day. When the central cornea was analyzed to detect DNA fragmentation, corneas treated before PRK showed 50% less apoptosis in keratinocytes.41

Clinical data to substantiate the value of CoQ10 administration in patients after cataract surgery is also available. A study in 40 patients undergoing uneventful cataract surgery and receiving either topical CoQ10 + vitamin E eye drops or saline solution were followed up for 9 months after the intervention. At day 14 and months 3, 6 and 9 patients were examined for signs and symptoms of OSD using Schirmer I test, BUT, non-invasive BUT, for defects in central and temporal nerve fiber density (CFD, TFD) at the subbasal nerve plexus (SBP) using confocal microscopy. Furthermore the Ocular Surface Disease Index (OSDI) was filled in. The authors demonstrated that surgery approximately halved TFD and reduced CFD by 25–35%. Nerves did regenerate in both patient groups during the following 9 months. However, the group receiving CoQ10 displayed an accelerated nerve regeneration and better recovery from signs and symptoms of OSD. At day 14, patients treated with CoQ10, already showed a physiological recovery of CFD that was comparable to 9 months of physiological recovery under saline solution. After 9 months the full SBP at the central cornea was recovered in 95% of patients using CoQ10 compared to only 80% treated with saline solution. After about 3 months of CoQ10 treatment, the SBP of the temporal cornea was fully recovered in 75% of patients using CoQ10. This result was comparable with the values after 9 months of saline treatment. (Graphic 4)

Graphic 4: Density of the sub-basal nerve plexus at the temporal cornea (number of fibers per field)

No relevant side effects were found, apart from an occasional burning sensation reported by 10% of CoQ10 patients. Findings show that changes of the corneal nerves occurring after cataract surgery may influence the integrity of the ocular surface and that topical treatment with CoQ10 combined Vitamin E has a positive effect on nerve regeneration and anatomy and ocular surface stability by restoring the SBP.42

Data from a mouse model also showed that CoQ10 prevents peripheral neuropathy and attenuates neuron loss in a type 2 diabetes mouse model. Apparently, reactive oxygen species and reduced PLCβ3 expression may contribute to sensory deficits in late-stage diabetic db−/db− mice, and early long-term administration of the antioxidant CoQ10 could represent a promising therapeutic strategy for neuropathy in type 2 diabetes.43

A recent systematic review and meta-analysis of existing data reported that CoQ10 supplementation has an impact on inflammatory markers and may therefore help downregulate the inflammation process.44

Dr. Benitez del Castillo concluded that overall “the addition of CoQ10 to the preoperative and postoperative standard of care, should reduce surgical damage, accelerate full patient recovery and decrease sequelae such as dry eye and neuropathic pain. The beneficial effect of CoQ10 should be further investigated by conducting well-defined longer-term clinical trials to help better understand the mechanism of action of this promising new approach.”

NEUROPROTECTION IN GLAUCOMACoenzyme Q10 and glaucoma: evidence and effects in the preservation of Retinal Ganglion Cells

Dr. Francesca Cordeiro, Professor of Ophthalmology, Imperial College London; Professor of Glaucoma and Retinal Neurodegeneration, UCL, London, UK

“I would like to share with you the available evidence on use of CoQ10 in glaucoma”, Dr. Cordeiro introduced her presentation and continued that “there is a clear unmet need in glaucoma. If you look at landmark glaucoma trials such as OHTS45, EMGT46 and CNTGS47 you will find that successful IOP reduction does not necessarily prevent loss of vision and this is where the concept of neuroprotection comes in.”

A better understanding of neurological or neuro-ophthalmological strategies for various ocular diseases involves taking a closer look at cell biology. There are various strategies targeting different causes of cell and tissue disorders such as inflammation, oxidative stress, protein misfolding and mitochondrial dysfunction. All of them have been put forward to help understand the nature of and to develop a cure for neurodegenerative diseases such as Alzheimer’s disease or glaucoma. In glaucoma, only 2 medications acting as potential neuroprotectants so far reached the stage of a randomized controlled trial in humans. In this plethora of possible strategies mitochondrial dysfunction appears to be a most interesting target.

The mitochondria are the powerhouse of the cell, where energy in the form of adenosine triphosphate (ATP) is produced in the intermembrane space. The cell’s life cycle is accompanied by regulatory mechanisms acting on the mitochondria. Within the mitochondrial respiratory chain Coenzyme Q10 (CoQ10) is essential for the production of ATP, where it serves as an electron transporter in complexes I, II and III. It also inhibits NF-B, a factor responsible for inflammation, autoimmune disease, virus infections and linked with cancer. CoQ10 also inhibits the opening of permeability transition pores (PTP) of the cell. CoQ10 derives its antioxidant nature from an electron carrier function, this means it continuously goes through a cycle of oxidation and reduction (redox cycle), by accepting electrons in its oxidized form and conversely giving up electrons in its reduced form. In the latter state, CoQ10 holds electrons rather loosely and thus may quite easily give up electrons, thereby acting as an antioxidant. Endogenous CoQ10 is present everywhere in the body. Levels decrease with age as demonstrated by measurements in liver, heart, kidneys and lungs.3

“So what value can topical application of Coenzyme Q10 add in ophthalmology?”, Dr. Cordeiro wants to know. She is aware that “this option has only recently become available. There is no comparison between topical and oral use yet, however, CoQ10 was detected in vitreous samples after eye dropapplication, demonstrating that it reaches the back of the eye. These findings are assuring to ophthalmologists, who prefer a topical route of administration in their patients”.

The indications for use of CoQ10 would include ocular surface as well as retinal diseases, since underlying mechanisms involve dysfunction of neurons. As already mentioned by Dr. Ahmad, CoQ10 has an effect on corneal keratocytes of rabbits, after cells had been exposed to apoptotic stimuli such as UV radiation, antimycin A and serum starvation. Application of CoQ10 prior to exposure, reduced apoptosis by a direct inhibition of mitochondrial depolarization.4

Additionally, data recently published by Dr. Cordeiro and her team has shown that cultured retinal ganglion cells (RGCs), having been exposed to the anti-mitochondrial toxin, dimethyl sulfoxide (DMSO), and consequently having suffered from an insult to the electron transport and oxidation chain can be protected by the use of topical CoQ10. Furthermore an in vivo glaucoma study in rats with unilateral surgically induced ocular hypertension (OHT) which reduces the absolute number and density of RGCs demonstrated that treatment with CoQ10 combined with Vitamin E (TPGS) or Vitamin E alone, twice a day for 3 weeks reversed RGC loss, both in vivo using DARC (detection of apoptotic retinal cells) and histologically. (Graphic 5)

Graphic 5: DARC analysis showing an increased amount of spots (=apoptotic retinal cells) in OHT eyes compared to the respective contralateral eyes. Amount of DARC spots are lower on the group treated with CoQ10/TPGS compared to TPGS only.

10 11Approved for distribution to Healthcare Professionals only Approved for distribution to Healthcare Professionals only

Results showed that the topical combination of CoQ10/Vitamin E had a significant neuroprotective effect by remarkably reducing apoptosis levels, with retinal cell values almost increasing back to those of naïve controls. This was not the case with Vitamin E alone. 48

Graphic 6: RGC density depending on the distance from the ONH in normal eye, eyes with raised IOP, eyes treated with CoQ10/Vitamin E or Vitamin E alone. There is a visible reduction in density in eyes with raised IOP. Eye treated with CoQ10/Vitamin E seem to have reengaged the normal mechanism into play, similar to control eyes, with no significant RGC loss. This is not the case with Vitamin E treated eyes.

“This could be a powerful way in reverting changes as result of insult on the retina”, Dr. Cordeiro concluded.49

Recently an early proof of concept study demonstrating clinical efficacy of CoQ10 in humans has been carried out in Italy. The researchers looked at the effect of topical CoQ10 in conjunction with vitamin E on retinal-evoked and cortical-evoked responses in 22 patients with OAG. Electrophysiological methods such as visually evoked potentials (VEP) and pattern electro-retinogram (PERG) were used to evaluate, whether use of CoQ10 in combination with vitamin E, could have any effect on the retinal function, on visual cortical responses and on neural conduction along the post-retinal visual pathways in patients with OAG. Patients had to be on topical beta-blocker monotherapy 8 months prior to electrophysiological evaluation. While one study arm continued to be treated with beta-blockers only, the other group administered beta-blockers and 2 drops per day of a topical fixed combination of CoQ10 100 mg and Vitamin E 500 mg (Coqun®). Patients were followed-up for 12 months. At six and twelve months both VEP and PERG showed improved amplitudes in the group treated with CoQ10/Vitamin E: Changes in VEP enhancement (reduction of time and amplitude) was seen in about 50% of CoQ10/Vitamin E patients, independent of baseline condition, demographics or disease parameters. VEP enhancement was only detected in patients, in whom an improvement of PERG responses was found. This suggests that better cortical responses depend on a reduction of RGC dysfunction. Changes in PERG responses were found in 60% of CoQ10/Vitamin E patients. Patients with greater retinal dysfunction at baseline showed better response to CoQ10/Vitamin E.50 This shows that there were not only structural but function change in patients.

Dr. Cordeiro summarized for the audience that “mitochondria play an important role in neurodegeneration. CoQ10 targets mitochondria, appears to reach back of the eye and seems to be an effective therapy to reverse mitochondrial dysfunction in glaucoma by preventing RGC apoptosis and functional loss. Apart from ischemic damage, CoQ10 can also counter reperfusion damage, as the level of apoptosis and ability to reverse this has an influence on muscle injury.CoQ10 also has its role in treating OSD. Further proof-of-concept studies with strong endpoints are needed.”

Outlook

The use of CoQ10 for dry eye treatment needs to be further differentiated. Some patients with persistent epithelial defects have experienced a good effect and this will need to be explored further. In general CoQ10 can improve the ocular surface by countering processes related to apoptosis. The optimal instillation frequency and length of treatment will also need to be further specified in longer-term clinical studies, keeping in mind that this depends very much on the individual need of the patient. Data relative to treatments targeting the inflammatory process in more severe forms of DED (DED accompanied by severe keratitis) such as cyclosporine have also recently become available.51

Future studies on the use of CoQ10 in glaucoma should determine how positive effects on electrophysiological parameters can be translated into preservation of visual field function.

Two ophthalmic formulations containing CoQ10 are offered by VISUfarma, a pan-European eye health company with headquarters in The Netherlands:

A fixed combination of cross-linked HA with CoQ10 and Vitamin E TPGS as a vehicle is now available in many European countries for dry eye relief and for aiding fast recovery following eye surgery. The product is classified as Medical Device.

In Italy, a fixed combination of 100 mg CoQ10 and 500 mg Vitamin E-TPGS in 100 ml of solution is marketed for complementary use with glaucoma therapy. The product is also a CE marked medical device and available to the public. According to the company, the product will become available in other European countries in the course of coming year.

1. Craig JP, Nichols KK et al. TFOS DEWS II Definition and Classification Report. Ocul Surf. 2017;15:276-283.

2. Baudouin C, Aragona P et al. Role of hyperosmolarity in the pathogenesis and management of dry eye disease: proceeding of the OCEAN group meeting. Ocul Surf. 2013 Oct; 11(4):246-58.

3. Kalen et al. Age-related changes in the lipid compositions of rat an human tissues. Lipids. 1989 Jul;24(7):579- 84.

4. Papucci L, Schiavone N et al. Coenzyme Q10 prevents apoptosis by inhibiting mitochondrial depolarization independently of its free radical scavenging property. J Biol Chem. 2003; 278:28220-8.

5. Emmanuele V et al. Heterogeneity of coenzyme Q10 deficiency: Patient Study and Literature Review. Arch Neurol. 2012 Aug;69(8):978-973. doi:10.1001/archneurol.2012.206.

6. Sander S et al. The Impact of Coenzyme Q10 on Systolic Function in Patients with Chronic Heart Failure. J Cardiac Failure. 2006 Aug;12(6):464-472.

7. Fotino AD, Thompson-Paul A, Bazzano LA. Effect of coenzyme Q10 supplementation on heart failure: a meta- analysis. Am J Clin Nur. 2013;97:268-75.

8. Chaturvedi R & Beal MF. Mitochondrial approaches for neuroprotection. Ann N Y Acad Sci. 2008 December;1147:395-412.doi:10.1196/annals.1427.027.

9. Chen CC, Liou SW et al. Coenzyme Q10 reduced ethanol-induced apoptosis in corneal fibroblasts. PloS One.2011;6(4): e19111.

10. Mencucci R, Favuzza E et al. CoQ10-containing eye drops prevent UVB-indiced cornea cell damage and increase cornea wound healing by preserving mitochondrial function. Invest Ophthalmol Vis Sci. 2014;55:7266- 71.

11. Wang S et al. Protective effect of Coenzyme Q10 against oxidative damage in human lens epithelial cells by novel locular drug carriers. Intern J Pharm. 2011 Jan;403(1-2):2019-229.

12. Lulli M, Witort E et al. Coenzyme Q10 instilled as eye drops on the cornea reaches the retina and protects retinal layers from apoptosis in a mouse model of kainite-induced retinal damage. Invest Ophtalmol Vis Sci. 2012; 53: 8295-302.

13. Noh et al. Xanthomonas oryzae pv. Oryzae RpfE Regulates Virulence and Carbon Source Utilization without Change of the DSF Production. Plant Pathol J. 2013 Dec;29(4):364-73.

14. Lee D, Kim KY et al. Coenzyme Q10 ameliorates oxidative stress and prevents mitochondrial alteration in ischemic retinal injury. Apoptosis. 2014;19:603-14.

15. Gumus K. Topical Coenzyme Q10 Eye Drops as an Adjuvant Treatment in Challenging Refractory Corneal Ulcers: A Case Series and Literature Review. Eye Contact Lens. 2017 Mar;43(2):73-80.

16. Kim J, Medsinge A., Chauhan B, Wiest C, Scanga H, Monaghan R et al. Coenzyme Q10 in the treatment of corneal edema in Kearns-Sayre: Is there any application in Fuchs endothelial corneal dystrophy? Cornea. 2016 Sep;35(9):1250-4.

17. Iester M et al. Improvement of the ocular surface using hypotonic 0.4% hyaluronic acid drops in keractoconjunctivitis sicca. Eye. 2000;14:892-98.

18. Fukuda K, Miyamoto Y, Miyara Y. Hyaluronic acid in tear fluid and its synthesis by corneal epithelial cells.Asia-pacific J Ophthalmo. 1998;40:62-65.

19. Kato T et al. Analysis of glycosaminoglycans in rabbit cornea after excimer laser keratectomy. Br J Ophthalmol. 1999;83:609-612.

20. Nishida T et al. Hyaluronan stimulates corneal epithelial migration. Exp Eye Res. 1991 Dec;53(6):753-8.

21. Miyauchi S et al. The effect of sodium hyaluronate on the migration of rabbit corneal epithelium. I. An in vitro study. J Ocul Pharmacol. 1990;6(2):91-99.

22. Gomes JAP, Amankwah R, Powell-Richards A, Dua HS. Sodium hyaluronate (hyaluronic acid) promotes migration of human corneal epithelial cells in vitro. Br J Ophthalmol. 2004;88:821-825.

23. Lerner LE, Schwartz DM, Hwang DG et al. Hyaluronan and CD44 in the human cornea and limbal conjunctiva. Exp Eye Res. 1998;67:481–4.

24. Entwistle J, Hall CL, Turley EA. HA receptors: signalling to the cytoskeleton. J Cell Biochem. 1996;61:569–77.

25. Yokoi N et al. Effectiveness of hyaluronan on corneal epithelial barrier function in dry eye. Br J Ophthalmol. 1997;81:533-536.

26. Aragona P, Papa V, Santocono M, Milao G. Long-term treatment with sodium hyaluronate containing artificial tears reduces ocular surface damage in patients with dry eye. Br J Ophthalmol. 2002 Feb;86(2):181-4.

27. Aragona P et al. Sodium hyaluronate eyedrops of different osmolarity for the treatment of dry eye in Sjögren’s syndrome patients. Br J Ophthalmol.

2002;86:879-884.28. Tezel A & Fredrickson GH. The science of hyaluronic acid

dermal fillers. J Cosmet Laser Ther. 2008 Mar;10(1):35-42.doi:10.1080/14764170701774901.

29. Cagini C et al. Tear Film Stability in Sjögren Syndrome Patients Treated with Hyaluronic Acid Versus Crosslinked Hyaluronic Acid-Based Eye Drops. J Ocul Pharmacol Ther. 2017 Sep;33(7):539-542.

30. Williams DL & Mann BK. Efficacy of a crosslinked hyaluronic acid-based hydrogel as a tear film supplement: a masked controlled study. PloS ONE. 2014 Jun 10;9(6):e99766.

31. Frei B, Kim M, Ames B. Ubiquinol-10 is an effective lipid-soluble antioxidant at physiological concentrations.Proc. Natl. Acad. Sci. 1990 Jun;87:4879-4883.

32. Postorino El, Rania L et al. Efficacy of eye drops containing cross-linked hyaluronic acid and coenzyme Q10 in treating patient with mild to moderate dry eye. Eur J Ophthalmol. 2017 Aug;doi:10.5301/ejo.5001011.

33. Benitez del Castillo JM et al. Decrease in tear secretion and corneal sensitivity after laser in situ keratomileusis. Cornea. 2011;20:30-32.

34. Benitez del Castillo JM et al. Relation between corneal innervation with confocal microscopy and corneal sensitivity with noncontact esthesiometry in patients with dry eye. Invest Ophthalmol & Vis Sci. 2007 Jan;48(1):173-81.

35. Li XM, Hu L, Hu J and Wang W. Investigations of Dry Eye Disease and Analysis of the Pathogenic Factors in Patients after Cataract Surgery. Cornea. 2007;26(Suppl. 1):S16-S20.

36. Khanal S, Tomlinson A, Esakowitz L, Bhatt P, Jones D, Nabili S et al. Changes in corneal sensitivity and tear physiology after phacoemulsification. Ophthalmic and Physiological Optics. 2008;28: 127-34.

37. Woodward MA et al. Dissatisfaction after cataract surgery and multifocal lens implantation. J Cataract Refr Surg. 2009 Jun;35(6):992-7.

38. Liu X et al. Changes of tear film and tear secretion after phacoemulsification in diabetic patients. Journal of Zheijang University Science B. ISSN 1862-1783 online at www.springerlink.com.

39. Sanchez MA, Arriola-Villalobos P et al. The effect of preservative free HP guar on dry eye after phacoemulsification: a flow cytometric study. EYE. 2010;24:1331-7.

40. Hwang TL et al. Magnesium ascorbyl phosphate and CoQ10 protect keratinocytes against UVA irradiation by suppressing glutathione depletion: fraction of surviving cells is increased. Molecular Medicine Reports. 2012 May;6:375-378.doi:10.3892/mmr.2012.933.

41. Brancato R et al. Concomitant effect of topical ubiquinone Q10 and vitamin E to prevent keratocyte apoptosis after excimer laser photoablation in rabbits. J Refract Surg. 2002;18:135-9.

42. Fogagnolo P, Sacchi M et al. The effects of topical CoQ10 + vitamin E D-alpha-tocopheryl glycol 1000 succinate after cataract surgery: a clinical and in vivo confocal study. Ophthalmologica 2013;229:26-31.

43. Sten Shi TJ, et al. CoQ10 prevents peripheral neuropathy and attenuates neuron loss in the db-/db/ mouse, a type 2 diabetes model. Proc Natl Acad Sci. 2013 Jan;11-(2):690-5.

44. Zhai J, Bo Y et al. Effects of CoQ10 on markers of inflammation. A systematic review and meta-analysis. PLoS ONE. 2017 Jan 26;12(1):e0170172.

45. Kass MA et al. The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open-angle glaucoma. Arch Ophthalmol .2002 Jun;120(6):714-20.

46. Heijl A, Leske C et al. Reduction of Intraocular Pressure and Glaucoma Progression. Results from the Early Manifest Glaucoma Trial. Arch Ophthalmol .2002;120:1268-1279.

47. Collaborative Normal-Tension Glaucoma Study Group. Comparison of Glaucomatous Progression Between Untreated Patients With Normal-Tension Glaucoma and Patients With Therapeutically Reduced Intraocular Pressure. Am J Ophthalmol .1998;126:487-497.

48. Davis BM, Tian K, Pahlitzsch M, Brenton J, Ravindran N, Butt G, Malaguarnera G, Normando EM, Guo L, Cordeiro MF. Topical Coenzyme Q10 demonstrates mitochondrial-mediated neuroprotection in a rodent model of ocular hypertension. Mitochondrion. 2017 Sep;36:114-123. doi: 10.1016/j.mito.2017.05.010. Epub 2017 May 24.

49. Nucci C, Tartaglione R et al. Retinal damage caused by high intraocular pressure-induced transient ischemia is prevented by coenzyme in rat. Int Rev Neurobiolo. 2007;82:397-406.

50. Parisi V, Centofanti M et al. Effects of coenzyme Q10 in conjunction with vitamin E on retinal-evoked and cortical-evoked responses in patients with open-angle glaucoma. J Glaucoma. 2014;23:391-404.

51. Baudouin C, de la Maza MS, Amrane M, Garrigue JS, Ismail D, Figueiredo FC, Leonardi A : One-year efficacy and safety of 0.1% cyclosporine A cationic emulsion in the treatment of severe dry eye disease. Eur J Ophthalmol. 2017 Jul 1:0. doi: 10.5301/ejo.5001002. [Epub ahead of print]

References

the eye health company

VISUfarma BVHead OfficeRembrandt Tower, 11th floor, Amstelplein 1 1096 HA Amsterdam

T: +31 (0)20 236 2200www.VISUfarma.com info@VISUfarma.com Twitter: #VISUfarma

Follow us on:

For more information about our products, please visit www.VISUfarma.com