Challenges

Updated since Sep 2009 and from time to time:

My findings so far :

Background

The human inner ear 's cells (commonly known as hair cells because they have hairs) grow very fast and furious in foetus in the mother's womb sometime around between 9 to 11 weeks. But then they stop growing after that. The about 15500 hair cells are all that there is for a human to listen in their life-time, because hair cells would not re-grow back once they died due to whatever reason (eg loud noise, virus infection , mini-stroke in the inner ear / blockage of the ear tiny blood vessels etc).

The 15500 hair cells are lined up inside the snail-shell shaped cochlea. The outer ones 'detect and hear' high/very high frequencies while the inner ones 'detect and hear' lower frequencies and transmit the information via the 8th nerve to the brain which then enable us to hear the sounds.

Any damage to the hair cells inside the cochlea and also to the nerve cells along the 8th nerve is generally known as sensorineural hearing loss. It is more common for the hair cells in the cochlea to be damaged than the nerve cells along the 8th nerve to be damaged.

Conventional medicine all said there is no cure for sensorineural hearing loss.

Then around 1987 , 2 team of scientists discovered birds can hear again after they are deafened and their hair cells can grow back after they died (therefore the phrase "there are no deaf birds"). Many other scientists then start to embark on the road to find a cure for sensorineural hearing loss (also known as nerve deafness). Related to the death of hair cells is Tinnitus and loss of balance.

Broadly these are the challenges to finding a cure for sensorineural hearing loss:

I. finding a cure -

1. Using Stem Cell as a cure

Recently (Mar 2009) Dr Marcelo Rivolta and team at University of Sheffield have for the 1st time in human history managed to re-grow human ear nerve in lab. So now tests can be done directly using human tissue instead of say mice's

Problems

- the cell do not have the characteristic hairs which lead to its name 'hair cell'
(but Marcelo team say they are confident they can perfect the growth)

- body may reject if the cell come from another person (solution : take medicine to suppress rejection)

- how to transplant them into the small 5 mm cochlea

- the stem cells may grow uncontrollably, causing non-lethal tumour or cancer tumour

But a team discovered in Apr 2008 a protein which kill cancerous stem cell (see :
http://www.bti.a-star.edu.sg/ASTAR_team_Develops_First_Cytotoxic_Antibody_against_Undifferentiated_Stem_Cells.pdf

Also see my other headings on main page of my blog).

2. Using Gene as a cure

By injecting turn-on gene (eg Atoh1 formerly known as Math1 / also known as Hath1) and at the same time injecting suppressing-turn-off gene (eg retinoblastoma or Rb1) into the cochlear.

How ?

By eg hijacking a virus (eg cow virus)

Scientists like Yehoash Raphael (2005) and John Brigande (2008) and KU Med researcher Dr. Hinrich Staecker (2009) have been working on gene theraby.

- Dr Staecker informed at Jun 2009 HLAA that they can change the number of hair cells they produce by changing the promoter
(ie. turning the dimmer switch on the Atoh1/Math1 gene up or down).

So I will say if they can find out how many hair cells needed by individual patient , then blavo, we are closer to a cure !

Problems

- sound restored by Atoch1 are distorted because only 1 out of 2 types of hair cell are re-grown
- danger of developing into non-lethal tumour or lethal cancer (but 'promoter' switch is possible solution)

Some other scientists are also looking into a new gene delivery engine using new OAD technology (see link*). So it is promising for people like me who has sensorineural hearing loss with T, where the main stream medicine field currently offered no cure. It is a possible substitute for the virus delivery engine currently thought to be the most likely candidate for delivering the Math1/Atoh1 hair-cell-growth- stimulating gene into the inner ear.

*See :http://www.nanobmi.com/images/OAD_Technology_for_Inner_Ear_Therapeutics_June_2009.pdf

3. Extracting and transplanting recently discovered brain matter who looked and behaved like inner ear hair cells

See :
http://health.msn.com/health-topics/ears-nose-throat/articlepage.aspx?cp-documentid=100231857


Problems

- unclear side-effect of taking out brain matter
- how to transplant into the small 5 mm cochlea

4. Drug

Some drugs being developed by some pharma companies for US Defence Dept for their soldiers to prevent hearing loss due to noise or to treat noise-induced deafness shortly after onset. Still development stage
- sound-induced drug is now being developed by coy
eg Pharma Sound
- there are other coy which is working on Atoh1/Math1
eg GenVec


5. Programming surviving hair cells

I have read and note some scientists have suggested they may be able to programme the remaining surviving hair cell to hear the sounds which the dead hair cells can no longer hear.

See :

http://www.ethlife.ethz.ch/archive_articles/080905_gehoerschnecke/index_EN


6. Cochlea Transplant

Cochlea transplant is not conducted yet.

It means the transplant of another person's real cochlea to the patient's inner ear (contrast this with Cochlear Implant which used a mechanical device).

Problem of connecting the 15500 hair cells nerves from cochlea to brain
(Query : But have anyone find out whether there is a really a need to connect each hair cell nerve to the brain ?)


II. Delivery


Problems -

Cochlea is tiny - only 5 mm
Cochlea is behind/protected by the body's hardest bone, the temporal bone - so it is more challenging to surgically drill through
Cochlea also filled with fluids (more than 1 fluids) - possible leakage if punctured.

Possibilities

By flooding the cochlea by injection into the inner ear
By nano technology (see my other headings on my main page of my blog)
By hijacking a harmless virus - but body immune system may attack it first
By yet-to-be-developed micro transplant surgery (to overcome problem of the 8th nerve being very very close to the face nerve and any incorrect handling might paralyse face)
By new technology (see above OAD technology as an example).


III. Clinical trials on humans

Too stringent and too long?
Block by ethical / moral issues ?

Should not be major issue : Once a cure or cures are found, some countries (like China) will spearheard and West will play catch-up again , like for stem cell treatments for blindness , eye and spinal injuries

1. As at Sep 2009, research is being done on using deaf babies cord blood stem cell to treat them by The CBR Center for Regenerative Medicine. It is collaborating with two leading medical institutions to initiate a research study that would evaluate using a child's own cord blood stem cells to help restore or improve hearing that's been damaged from injury or sickness from Feb 2009.

So if it succeed, it proved stem cells do grow into human inner ear cochlea's hair cells and the 8th nerve cells which connect sounds from the cochlea to the brain, which will enable hearing to be restored.

See :
http://www.cordblood.com/regenerative-medicine/hearingloss.asp


2. Then in Sep 2009, there are e-mail replies from a China hospital in Qingdow that they can treat sensorineural hearing loss.

See :

Article 1
http://translate.google.com/translate?hl=es&sl=zh-CN&tl=en&u=http%3A%2F%2Fwww.ganxibao.com.cn%2FnewEbiz1%2FEbizPortalFG%2Fportal%2Fhtml%2FMessageBoard.html%3FMessageBoard_action%3DlistMultiPage%26MessageBoard_NextPage%3D35%26time%3D1252427645882%231 (external link, opens new browser window)

Article 2 -

Which says that the centre has treated a few cases of sensorineural hearing loss and results are not bad. Currently they are treating a girl who was born with SHL and there are some positive results already. For more details , can call them at 053280653989,80653375.

The link in Chinese
http://www.ganxibao.com.cn/newEbiz1/EbizPortalFG/portal/html/MessageBoard.html?MessageBoard_action=listMultiPage&MessageBoard_NextPage=1&time=1252374159945#1 (external link, opens new browser window)


IV. Funding

Should not be major issue : Once plausible cures found or plausible theories out, venture companies , investors and pharma companies will come in because the market is huge

1. There is funding by governments

eg US' Department of Defence,

eg US' NIDCD

See :

http://www.thomas.gov/cgi-bin/cpquery/?&sid=cp111ZXgCA&refer=&r_n=sr066.111&db_id=111&item=&sel=TOC_411259&

2. Then there is at least 1 venture coy which is trying to get $20 million ie $20,000,000 for treating mienere disease and hearing loss. See
http://www.xconomy.com/san-diego/2009/03/06/otonomy-tunes-in-to-biotechs-sound-opportunity-diseases-of-the-ear/


3. There is also individual donation.