N-Acetyl
Carnosine - Is It The Cure For
Cataract?
by Robert Mason Ph.D.
In Russia over the last several years, they have been researching a special
analogue of the di-peptide carnosine. This particular form is known as
n-acetylcarnosine or NAC and it has been proven to be highly efficacious in the
treatment of cataract and may also present a case for the prevention of the
same. This article is about the case for NAC and the problems associated with
senile-cataract.
Cataract is the leading cause of blindness and accounts for about 42% of all
such cases worldwide, and this is in-spite of the availability of effective
surgical treatment. Today we have the appalling situation where more than 17
million people around the world are blind because of cataract and 28,000 new
cases are reported everyday. In developing countries, there is simply not a
sufficient number of surgeons to perform cataract operations.
Cataract surgery is the most commonly performed surgical procedure in people
over 65-years of age, and 43% of all visits to ophthalmologists by Medicare
patients in the US are directly associated with cataract.
Meanwhile, approximately 25% of the population over 65 (and about 50% over
80) have a serious loss of vision due to cataract. Since this is the population
that is most susceptible to lens opacification and as this section of the
population is expected to increase dramatically, the numbers of individuals with
cataract is set to explode!
For example, the World Health Organization anticipates that within the next
25-years, that 20% of the population will be 65 or older. Furthermore, the
single largest growing section of the population are those over 85 and their
actual numbers are expected to quadruple in about the same period. Such a
rapidly burgeoning older population can only increase the numbers of individuals
suffering from cataract.
Of course, there is also the economic impact. Currently 1.35 million cataract
operations are performed annually in the United States alone and Medicare
estimates the annual cost at $3.5 billion! There's no doubt about it, cataract
is a major disease.
It is also becoming apparent that it will not be possible to eliminate the
overall problems (including blindness), caused by cataract with the current
procedures. With so many people presenting the afflictions of maturity onset
cataract, it appears not to be possible to train in-time, the necessary
numbers of surgeons required. In-fact, as-it-stands, it looks likely that the
total number of people with serious eye-disorders because of cataract, will
increase dramatically worldwide.
Surgical complications
There is another aspect to the problem that is rarely discussed. While
cataract surgery is generally recognised as being one of the safest operations,
there is a significant complication rate. For example, in the United States 30%
to 50% of all patients having cataract extraction, develop opacification of the
posterior lens capsule within two years and require further lazer treatment.
Since the number of cataract operations is so large, even a small percentage
of complications represents a significant number of people. Of the patients
having cataract surgery, 0.8% have retinal detachments, 0.6% to 1.3% are
hospitalized for corneal edema (or require corneal transplantation), and
0.1% present endophthalmitis.
Thus, aside from secondary cataract, about 2% of the 1.35 million (or
approximately 27,000 individuals), just in the US each year, develop
serious complications as a result of cataract surgery.
It is therefore difficult to support the argument that cataract research is
unimportant with statistics such as those cited above. The large and growing
number of people blind with cataract and the significant complication rate,
should be sufficient reason to increase cataract research.
The considerable discomfort experienced by patients as their vision
diminishes, and the complete loss of accommodation resulting in the removal of
the lens should also be recognised. Besides the possible complications, an
artificial lens just does not have the overall optical qualities of a natural
lens.
A medical solution is required that will maintain the transparency of the
lens. Even if the development of cataract can be delayed by 10-years, the
overall benefits would be highly significant.
The development of NAC
Innovative Vision Products (IVP) utilizing Russian researchers and scientists
has developed and tested a unique new form of carnosine. This form of carnosine
is known as N-Acetyl Carnosine or abbreviated to NAC.
NAC presents the first major leap forward in the treatment and possible
prevention of senile cataract.
As a bio-engineering company, IVP has developed a proprietary method of
producing extremely high purity NAC that has proven to be a suitable
ophthalmic drug for the non-surgical treatment of age-related cataracts.
NAC has a highly statistical and very significant clinical success rate for
patients within 3-12 months of treatment. Not surprisingly, IVP has been quick
to ensure that its NAC has worldwide patents, including its use for cataract. It
is also interesting to note that NAC eye-drops are patented for use in
open-angle glaucoma, but as yet, the research for that disorder remains
unpublished.
Human trials
Carnosine eye-drops were used in a clinical trial to treat 96 patients aged
60 and above. All the patients had senile cataract in various degrees of
maturity. The duration of the disease in these patients ranged between 2 and 21
years.
Firstly, the researchers stopped the patients use of all other anti-cataract
drugs. Then the patients instilled 1 or 2 drops into each eye 3 or 4 times a
day, for a period of 3 to 6 months.
The level of eyesight improvement and the change of lens transparency was
considered as an evaluation index. The results showed that there was a
pronounced effect on primary senile cataract, the effective rate was 100%
(i.e. all patients experienced an improvement). For the more mature senile
cataract (i.e. those who had had the cataract the longest time, in some
cases more than 20-years) the effective rate was still an extremely impressive
80%.
These are remarkable results considering that the best that could normally be
expected would be a slight improvement, a halt to the progression and under
normal (i.e. non-treated) circumstances a continual worsening of the disease.
Importantly, it was also noted that there were no side effects noted in any
of the cases.
Another Russian study was designed to document and quantify the changes in
lens clarity over a 6 to 24 month period for 49 volunteers. Their average age
was 65 and all suffered from senile cataract of a minimal to advanced
opacification.
The patients received either a 1% solution of NAC eye-drops or a placebo, as
2-drops twice a day into each eye. The patients were then evaluated at 2 and 6
month periods. The tests consisted of ophthalmoscopy (glare test),
stereocinematagraphic (slit-image) and retro-illumination (photography). A
computerized digital analysis then displayed the light scattering and absorbing
effects of the centers of each lens.
At 6-months, 88.9% of all eyes treated with NAC had an improvement of glare
sensitivity (lowest individual score was a 27% improvement, right the way up to
a 100% improvement). 41.5% of all eyes treated with NAC had a significant
improvement of the transmissivity of the lens, but perhaps most
importantly 90% of the eyes treated with NAC showed an improvement in visual
acuity. Meanwhile, in the placebo group there was little change in eye quality
at 6-months and a gradual deterioration at 12 to 24 months.
Importantly, this study also showed that at 24-months the NAC treated group,
(who already had significant improvement to the quality of their eyesight),
sustained these results with continued use of the NAC eye-drops.
Once again, no significant side effects were noted in any cases throughout
the 2-year period.
Another interesting study also evaluated patients between the ages of 48 and
60, who had various degrees of eyesight impairment, but who did not have
the symptoms of cataract. After a course of treatment ranging from 2 to 6 months
the conclusion was, that the eye-drops alleviated eye-tiredness and continued to
improve eyesight (i.e. there was more clear vision). The subjects reported that
the treatment "brightened" and "relaxed" their eyes. This is
an important indicator that the eye-drops have a value both for preventative
purposes, as well as medical applications.
At this time, it is now believed that carnosine eye-drop treatment has been
applied to over one thousand patients with senile cataract in China and Russia,
(those countries are home to the principal researchers behind the work). Clear
evidence is emerging that NAC eye-drops are a safe, effective treatment and
potential preventative against cataract.
NAC method of action
Cataract is a glycosylation problem. This reaction occurs when
proteins became cross-linked (and hence impaired). The result of this reaction
leads to the discoloration of the eye-lens to yellow and brown, and hence the
impairment of vision. But, carnosine is known to compete on the molecule for the
glycating agent and protect cellular structures against aldehydes.
Therefore, carnosine can slow and help to prevent proteins from becoming
cross-linked, (and in this case from becoming cataract).
NAC has been shown to be highly resistant to carnosinase, (the natural
enzyme that breaks down L-carnosine into histamine etc.). An experiment on
rabbits showed that NAC eye drops allow themselves to be broken down into
L-carnosine once inside the eye's aqueous humor, (a process that occurs within
15 to 30 minutes after application of the eye-drops).
L-carnosine is an excellent anti-oxidant and is particularly effective
against potent free-radicals, especially the Superoxide and the Hydroxyl.
It is therefore presumed, that the anti-oxidant role of L-carnosine (within the
aqueous humor) is a major factor, in slowing and preventing the appearance of
cataract.
However, when L-carnosine eye-drops were used there was no
presence of L-carnosine in the aqueous humor (even after 30-minutes). This may
be because L-carnosine is broken down early into histamine etc., before it
reaches the aqueous humor. So, NAC may act as a "carrier" for
L-carnosine delivering it to where it is needed.
The powerful anti-oxidant abilities of carnosine within the eye, and the
prevention of cross-linking, helps to explain why NAC is effective at preventing
and slowing cataract, perhaps even halting it. But it doesn't explain why NAC
has been shown to reverse cataract. But we may already know the answer.
For example, it is known that when carnosine is delivered in high doses, that
it can reverse protein-aldehyde cross-linking, (this reaction is normally very
difficult to reverse). Under these circumstances, carnosine has been shown to
have a "rejuvenating" effect on cultured cells.
Cataract develops when anti-oxidant defense is exhausted, leading to the
cross-linking of the lens crystallins, (producing a clouded lens, and
hence impaired eyesight). We can assume that the regular use of a 1% NAC
eye-drop (as used in the clinical trials), delivers "a high-dose of
carnosine capable of reversing the lens cross-linking," and hence the
reduction and eradication of cataract.
So in conclusion, NAC eye-drops appear to act as a universal anti-oxidant,
both in the lipid phase of the cellular lens membranes, and in the aqueous
environment. NAC eye-drops reduce and protect the crystalline lens from
oxidative stress-induced, cross-linking damage.
NAC compared to L-carnosine
We may logically ask the question; why have NAC eye-drops been shown to have
this action upon cataract, and yet L-carnosine (which is its sister di-peptide)
appears to have little benefit? Dr. Mark Babizhayev, one of the principal
Russian researchers behind the clinical trials with NAC eye-drops gave us this
reply to that very same question:
"I believe that the application of L-carnosine for the treatment of
human cataracts is misleading. This is because L-carnosine readily becomes a
substrate for the activity of natural peptidases (i.e. carnosinase) in the
aqueous humor. So much so, that there is no sign of L-carnosine in the
aqueous humor within 15 minutes after instillation. Furthermore, I consider that
L-carnosine eye-drops may even be harmful for eyes because it gradually releases
histamine, which, located as it would be in the presence of the eye-lens is a
very toxic agent. However, NAC eye-drops are resistant to hydrolysis with
natural carnosinase. Therefore, NAC is the only currently known agent which
reverses and prevents human cataracts."
In conjunction with Dr. Hipkiss and Dr. Kyriazis information, we can conclude
that while some of the benefits of oral L-carnosine may derive after
carnosinase breaks down into histamine.
It is also interesting to note that a study by Dr. Boldyrev et al, also
concluded that the oral use of NAC was far less likely to be broken down
by carnosinase than L-carnosine [click to Dr. Kyriazis
interview
for further details].
Dr. Mark Babizhayev also makes it quite clear that "ordinary" NAC
will not be of much use in the treatment of senile-cataract. This is because
there are many synthesized "carnosines" and their biological and
medicinal activity strongly varies and depends on the mode of their obtention.
[click to Dr. Babizhayev interview for further details].
For example, if carnosine is extracted from meat muscle substances, the
biological and anti-oxidant activity is very low. This is presumably due to the
contamination of the "pure" carnosine substance by heavy metal salts
and proteins and other related impurities. It is very difficult to purify
carnosine chromatographically, as the compound chelates divalent metal ions very
heavily and the biological and anti-oxidant activities can not be regenerated
during the purification procedures.
In conclusion, there were many forms of carnosine which were abandoned in the
Russian studies because of their lack of anti-cataract and anti-oxidant ability
in the human eye.
However, IVP (in conjunction with their Japanese partner and manufacturer),
has developed a synthesized pure NAC which has biological activity and has been
well controlled and proven in human lens studies. This is the same type that has
been used in the clinical trials.
Cataract is a widespread age-related affliction and NAC eye-drops appear to
be a highly efficacious and safe treatment for cataract. As such, I suspect that
this supplement is going to become one of the most important new discoveries,
and will have a major impact on the way that cataract is controlled.
References
Can-C eye drop testimonials
click
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