Stem Cell Treatment for Optic Nerve Atrophy: How It Works & What to Expect?

Optic nerve atrophy (ONA) is a condition that damages the optic nerve. The role of optic nerve is to transmit signals from the eye to the brain. It is also known as optic atrophy since it causes long-term damage to the optic nerve. It can impact vision and sometimes lead to blindness. 

Retinal ganglion cells are neurons that transmit signals from the retina to the brain, and the axons of these cells constitute the optic nerve. So, any damage to the retinal ganglion cells affects the optic nerve and leads to ONA. 

With no defined cure for the disease, stem cell therapy can restore vision loss and regenerate damaged tissue. 

Causes of Optic Nerve Atrophy 

A variety of factors or causes of Optic Nerve Atrophy, including genetic factors. They are

1. Ischemic optic neuropathy: Lack of blood supply to the optic nerve disrupts the functions of the optic nerve and leads to sudden vision loss.

2. Glaucoma: Conditions like glaucoma increase pressure inside the eye and damage the optic nerve.

3. Infection or injury: Infection, trauma or injury to the eye can also impact the optic nerve and affect vision.

4. Inflammation: Inflammation of the optic nerve, i.e., optic neuritis, also can trigger ONA.

5. Toxin exposure and nutritional deficiency: Exposure to toxins and nutritional deficiencies can leave an impact and damage the optic nerve.

How is nutritional deficiency associated with Optic Nerve Atrophy 

Deficiency of nutrients, especially vitamins, contributes to the development of Optic Nerve Atrophy. According to WHO, around 2, 50,000 to 5, 00,000 children suffering from vitamin A deficiency have vision loss. 

One such example is that of an 8-year-old Malaysian boy who lost his vision suddenly. On examination, it was found that the child had vitamin A deficiency, which affected his optic nerves and contributed to sudden vision loss. 

Therefore, it is important to incorporate enough nutrients in the diet to prevent optic nerve damage and vision loss. 

Types of Optic Nerve Atrophy 

1. Primary Optic Nerve Atrophy: It is a type where an injury or trauma directly damages the optic nerve.

2. Secondary Optic Nerve Atrophy: In this type, certain conditions like glaucoma or optic neuritis indirectly damage the optic nerve.

Symptoms related to vision are:

1. Vision loss or blurry vision

2. Peripheral vision damage

3. Alteration of colour vision

4. Difficulty in distinguishing colour

New treatment for Optic Nerve Atrophy 

• Neuroprotective interventions: Certain medications and pharmacological agents, such as anti-oxidants, provide neuroprotection and reduce inflammation and oxidative stress. They also prevent further damage by slowing down disease progression. 

• Optic Nerve Stimulation: It is a type of treatment strategy where an electrical device is fitted in the optic nerve. The device generates electrical impulses that stimulate the optic nerve, which regenerates nerve fibers and restores vision. 

• Visual aids: Aids such as electronic readers or glasses and magnifiers help improve vision in patients with optic atrophy. 

• Rehabilitation strategies: Counselling and specialized training can help improve challenges and can help cope with vision loss. 

• Retinal implants: These devices are implanted in the eyes, bypassing the damaged optic nerve and directly stimulating the retina. Such devices help regain the loss of sight to some extent. 

• Gene therapy: Genetic therapy is a therapy where mutated genes are replaced with healthy genes to restore vision loss. However, gene therapy carries its own set of risks. 

Stem Cell Treatment for Optic Nerve Atrophy 

The main goal of the stem cell therapy is to regenerate and restore damaged tissue and lost functions. Stem cell therapy in Optic nerve atrophy restores vision and replaces damaged retinal ganglion cells by releasing certain growth factors. 

It addresses two issues: 

1. Replacing and regenerating damaged retinal ganglionic cells

2. Preserving vision and preventing secondary damage.

Mechanism of stem cells for Optic Nerve Atrophy 

1. Release of neurotrophic factors

Stem cells release factors such as Vascular endothelial growth factor (VEGF), fibroblast growth factor, and Nerve growth factor (NGF) during tissue regeneration. They also release Neurotrophic factor (NT-3), Ciliary neurotrophic factor (CNTF), which enhance the survival of Retinal ganglion cells (RGCs) and Brain-derived neurotrophic factor (BDNF), which provide neuroprotection. Additionally, after the optic nerve injury, the Glial cell-derived neurotrophic factor (GDNF) promotes the survival of RGCs. 

2. Immunomodulation

Stem cells travel to the injured tissue, inhibit release of inflammatory cytokines and enhance the survival of damaged cells. They inhibit the production of TNF22, which reduces inflammation and promotes regeneration.  

Stem cells reduce TNF-α, IL-1β, IL-6, IL-8, and MCP-1 inflammatory cytokines levels and enhance IL-6 and IL-10 levels, which initiates neurogenesis and modulates the immune response. They also enhance the survival of retinal ganglionic cells by secreting Neurotrophic factor (NTF). 

3. Paracrine effects

Stem cells exert a paracrine effect by releasing paracrine factors and cytokines. The released cytokines prevent the apoptosis of neurons. They also enhance the expression of NTF. 

Role of Exosomes in ONA 

Exosomes are extracellular vesicles that contain lipids, proteins, miRNAs and mRNAs. The components of exosomes are essential for retinal function. Exosomes elicit certain cellular responses. The responses are 

1. Tissue repair and regeneration

2. Ameliorating immune response

3. Attenuating apoptosis of retinal cells

4. Reducing inflammatory cytokines expression

5. Enhancing survival of RGCs

6. Providing neuroprotection.

What positive perks can one expect with stem cell therapy?

1. Restoration of vision

2. Neuroprotection

3. Slows down disease progression

4. Reduces inflammation and pain

5. Improves overall quality of life.

Assessment of optic nerve function

In order to evaluate the migration of cells, localization, and axonogenesis, several tests are recommended. They are: 

1. To detect expression of NTF along with growth factors – ELISA, chain reaction, RT-PCR and western blot.

2. For visual nerve function – Flash visual evoked potential (f-VEP)

3. For measuring retinal nerve fiber layer – Optical coherence tomography (OCT)

4. To trace Retinal ganglion cells (RGCs) – Fluorogold (FG).

Conclusion 

With no existing cure for the treatment of optic nerve atrophy, the use of stem cell therapy has paved the way for its treatment. The collaborative implementation of stem cells restores vision loss in optic nerve atrophy. Both stem cells and exosomes have proven their ability to treat optic nerve damage. Therefore, with further research and trials, stem cell therapy can be established as the go-to therapy for optic nerve atrophy. 

FAQs 

Q: Define Optic nerve atrophy.

Optic nerve atrophy is a condition that damages the optic nerve. The role of optic nerve is to transmit signals from the eye to the brain. It is also known as optic atrophy since it causes long-term damage to the optic nerve. It can impact vision and sometimes lead to blindness. 

Q: What are the two types of Optic nerve atrophy?

Primary ONA is a type where an injury or trauma directly damages the optic nerve, and secondary ONA is where certain conditions like glaucoma or optic neuritis indirectly damage the optic nerve. 

Q: How does stem cell therapy work in optic atrophy?

Stem cells in Optic nerve atrophy restore vision by replacing damaged retinal ganglion cells and releasing certain growth factors to reduce inflammation and promote the survival of neurons. 

Q: What positive perks can one expect with stem cells?

The positive perks that one can expect in optic atrophy are restoration of vision, neuroprotection, reduction of inflammation and pain, slowing of disease progression and improvement of overall quality of life.