Cannabinoids for treatment of glaucoma.

“The purpose of this article is to review the current status of cannabis in the treatment of glaucoma, including the greater availability of marijuana in the USA.

The pharmacology of marijuana and its effect on intraocular pressure has not changed since the research in the 1970s and 1980s.

Marijuana is an effective ocular hypotensive agent.

However, cardiovascular and neurological effects are observed at the same dose, and may theoretically reduce the beneficial effect of lowering intraocular pressure by reducing ocular blood flow. The clinician must be cognizant of this potential in diagnosis, prognosis, and therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/26840343

Expression and Function of the Endocannabinoid System in the Retina and the Visual Brain.

“Endocannabinoids are important retrograde modulators of synaptic transmission throughout the nervous system.

Cannabinoid receptors are seven transmembrane G-protein coupled receptors favoring Gi/o protein. They are known to play an important role in various processes, including metabolic regulation, craving, pain, anxiety, and immune function.

In the last decade, there has been a growing interest for endocannabinoids in the retina and their role in visual processing.

The purpose of this review is to characterize the expression and physiological functions of the endocannabinoid system in the visual system, from the retina to the primary visual cortex, with a main interest regarding the retina, which is the best-described area in this system so far.

It will show that the endocannabinoid system is widely present in the retina, mostly in the through pathway where it can modulate neurotransmitter release and ion channel activity, although some evidence also indicates possible mechanisms via amacrine, horizontal, and Müller cells.

The presence of multiple endocannabinoid ligands, synthesizing and catabolizing enzymes, and receptors highlights various pharmacological targets for novel therapeutic application to retinal diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/26839718

Seeing over the horizon – targeting the endocannabinoid system for the treatment of ocular disease.

“The observation that marijuana reduces intraocular pressure was made by Hepler and Frank in the 1970s. Since then, there has been a significant body of work investigating cannabinoids for their potential use as therapeutics.

To date, no endocannabinoid system (ECS)-modulating drug has been approved for clinical use in the eye; however, recent advances in our understanding of the ECS, as well as new pharmacological tools, has renewed interest in the development of ocular ECS-based therapeutics.

This review summarizes the current state-of-affairs for the use of ECS-modulating drugs for the treatment of glaucoma and ocular inflammatory and ischemic disease.”

http://www.ncbi.nlm.nih.gov/pubmed/26565550

[CANNABIS AND GLAUCOMA: AN ANCIENT LEGEND OR A NOVEL THERAPEUTIC HORIZON?].

“Glaucoma causes damage to the optic nerve and compromises the visual field. The main risk factor of the disease is the level of the intra-ocular pressure. Therapeutic options include medical and surgical treatment, aimed to lower the intra-ocular pressure.

Consumption of the cannabis plant (Cannabis Satival has been known since ancient times. It can be consumed orally, topically, intra-venous or by inhalation.

The main active ingredient of cannabis is THC (Tetra-Hydro-Cannabinol). One of THC’s reported effects is the reduction of intra-ocular pressure.

Several studies have demonstrated temporary intra-ocular pressure decrease in both healthy subjects and glaucoma patients following topical application or systemic consumption.

Cannabis may be considered as a therapeutic option in glaucoma.”

http://www.ncbi.nlm.nih.gov/pubmed/26281086

Therapeutic potential of cannabis-related drugs.

“In this review, I will consider the dual nature of Cannabis and cannabinoids.

The duality arises from the potential and actuality of cannabinoids in the laboratory and clinic and the ‘abuse’ of Cannabis outside the clinic.

The therapeutic areas currently best associated with exploitation of Cannabis-related medicines include pain, epilepsy, feeding disorders, multiple sclerosis and glaucoma.

As with every other medicinal drug of course, the ‘trick’ will be to maximise the benefit and minimise the cost.

After millennia of proximity and exploitation of the Cannabis plant, we are still playing catch up with an understanding of its potential influence for medicinal benefit.”

http://www.ncbi.nlm.nih.gov/pubmed/26216862

Biomedical benefits of cannabinoids?

“Cannabinoids appear to be of therapeutic value as antiemetics, antispasmodics, analgesics and appetite stimulants and may have potential uses in epilepsy, glaucoma and asthma.

This paper reviews the clinical trials which have been carried out with cannabinoids including Δ⁹-tetrahydrocannabinol (THC) and synthetic cannabinoids such as nabilone and levonantradol, and discusses the advantages and adverse effects of cannabinoids in clinical use.

The place of cannabinoids in modern medicine remains to be properly evaluated, but present evidence suggests that they could be valuable, particularly as adjuvants, for symptom control in a range of conditions for which standard drugs are not fully satisfactory.”

Cannabinoid-induced chemotaxis in bovine corneal epithelial cells.

Cannabinoid CB1 receptors are found in abundance in the vertebrate eye, with most tissue types expressing this receptor. However, the function of CB1 receptors in corneal epithelial cells (CECs) is poorly understood. Interestingly, the corneas of CB1 knockout mice heal more slowly after injury via a mechanism proposed to involve protein kinase B (Akt) activation, chemokinesis, and cell proliferation. The current study examined the role of cannabinoids in CEC migration in greater detail…

In summary, we find that CB1-based signaling machinery is present in bovine cornea and that activation of this system induces chemotaxis.”

http://www.ncbi.nlm.nih.gov/pubmed/26024113

http://medical-dictionary.thefreedictionary.com/chemotaxis

Neuroprotective effect of (-)Delta9-tetrahydrocannabinol and cannabidiol in N-methyl-D-aspartate-induced retinal neurotoxicity: involvement of peroxynitrite.

“In glaucoma, the increased release of glutamate is the major cause of retinal ganglion cell death. Cannabinoids have been demonstrated to protect neuron cultures from glutamate-induced death.

In this study, we test the hypothesis that glutamate causes apoptosis of retinal neurons via the excessive formation of peroxynitrite, and that the neuroprotective effect of the psychotropic Delta9-tetrahydroxycannabinol (THC) or nonpsychotropic cannabidiol (CBD) is via the attenuation of this formation.

These results suggest the potential use of CBD as a novel topical therapy for the treatment of glaucoma.

“Cannabinoid components of marijuana, such as (−)Δ9-tetrahydrocannabinol (THC), or the synthetic cannabinoid WIN55,212-2, have been shown to prevent glutamate- or NMDA-induced neurotoxicity in isolated neurons or in the brain via activation of the cannabinoid receptor subtype CB1.

…the nonpsychotropic component of marijuana, cannabidiol (CBD), and the synthetic nonpsychotropic cannabinoid, HU-211, as well as THC have been demonstrated as potent antioxidants and/or NMDA receptor antagonists that protect neuron cultures from glutamate-induced death or from oxidative stress.

… we demonstrated that THC and CBD are neuroprotective against NMDA-induced retinal injury and that their protective actions are in part because of an effect in reducing formation of lipid peroxides, nitrite/nitrate, and nitrotyrosine.

In addition to possessing neuroprotective or retinal neuroprotective activity as demonstrated here and elsewhere, cannabinoids such as THC, WIN55,212-2, endogenous cannabinoid 2-arachidonoylglycerol, as well as nonpsychotropic HU-211 have been demonstrated to induce dose-related reductions in intraocular pressure in human and in animal models.

 This suggests that cannabinoids may offer a multifaceted therapy for glaucoma.

In conclusion, our results indicate that lipid peroxidation and ONOO− formation play an important role in NMDA-induced retinal neurotoxicity and cell loss in the retina, and that THC and CBD, by reducing the formation of these compounds, are effective neuroprotectants.

The present studies could form the basis for the development of new topical therapies for the treatment of glaucoma.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1892413/

http://www.thctotalhealthcare.com/category/glaucoma-2/

Neuroprotective effects of cannabidiol in endotoxin-induced uveitis: critical role of p38 MAPK activation.

“Degenerative retinal diseases are characterized by inflammation and microglial activation.

The nonpsychoactive cannabinoid, cannabidiol (CBD), is an anti-inflammatory in models of diabetes and glaucoma.

We tested the hypothesis that retinal inflammation and microglia activation are initiated and sustained by oxidative stress and p38 mitogen-activated protein kinase (MAPK) activation, and that CBD reduces inflammation by blocking these processes…

Retinal inflammation and degeneration in uveitis are caused by oxidative stress.

CBD exerts anti-inflammatory and neuroprotective effects by a mechanism that involves blocking oxidative stress and activation of p38 MAPK and microglia.”

http://www.ncbi.nlm.nih.gov/pubmed/19052649

[The role of endocannabinoid system in physiological and pathological processes in the eye].

“Plant of Cannabis sativa/ marihuana except for its psychotropic effects possesses a range of pharmacological properties, that has been utilized for medical purposes over a period of millenia.

Investigations concerning biochemical mechanism of action of the main and most active pharmacological compound of Cannabis sativa, cannabinoid 9-THC, contributed to the discovery of cannabinoid receptors both in the central nervous system (CNS) and peripheral tissues, that mediated actions of this substance.

The discovery made possible identification of a new, endogenous signaling system referred to as the endocannabinoid system.

Besides cannabinoid receptors CB1 and CB2, the system includes it’s endogenic ligands (endocannabinoids) and compounds that participate in their biosynthesis and inactivation. Structure and functioning of the endocannabinoid system is conservative in all vertebrates.

It’s activation with plant, synthetic and endogenous cannabinoids has an influence on multiple physiological and pathological processes within the eye.”

http://www.ncbi.nlm.nih.gov/pubmed/19195174