Nitric
Oxide and its Role in Health and Diabetes.
Part
12. The
Current Science and Benefit of Nitric Oxide and
Diabetes.
Diabetic patients,
their physicians and health care providers, including certified
diabetic educators, all recognize that diabetes
is a disease in which blood flow slowly and insidiously decreases over
time. The heart, kidneys, eyes, skin, and nerves all exhibit signs
of reduced blood flow. One organ may show symptoms earlier than
another, but all organs eventually demonstrate reduced function
associated with the progressive decrease in blood flow. The key to slowing this progressive deterioration of organ function is
to delay the decrease in blood flow, or if possible, to restore it
back toward normal levels.
The body’s
natural vasodilator is nitric oxide (NO) but its production by
diabetic patients is often 50% or more below normal levels.
In addition, any NO that is formed is very tightly bound to
hemoglobin within RBCs (and possibly to other heme proteins in other
cells) so that it cannot be easily released to cause a needed increase
in blood flow.
The past articles
in this series have shown that there are several ways to increase the
production or the local release of NO. Oxygen is critical to NO
production but with poor circulation to sites such as nerves and skin,
not enough oxygen is available to fully activate the enzyme that
generates NO from the amino acid L-arginine. In addition, as blood
flow decreases, the generation of ATP (from oxygen and glucose)
diminishes and high amounts of acid molecules are formed.
Acidosis also diminishes the production of NO. Since production
is diminished, the only readily useful source of NO is that already
stored in cells, such as RBCs. The
problem is how to release the stored NO so that local vasodilation can
occur. The Anodyne Therapy System™ (ATS), mentioned several times in
this series, turns out to be an easy to use, efficacious,
non-invasive, drug free way to accomplish the local release of NO from
RBC. The ATS uses near infrared light (NIR) that penetrates far deeper
into tissues than do shorter wavelengths such as ultraviolet (UV).
Why is a wavelength
of light so effective in releasing NO from RBC? To answer this
question one must acknowledge the important contributions of
physician/scientists who have studied NO for so many years. The 1998
Noble Prize in Medicine or Physiology was awarded to three Americans,
one of whom, Dr. R.F. Furchgott, noted that NO could be made available
acutely when he shined white light on tissues and that, as a result,
blood flow increased. Since light is made up of several different wave
lengths (or colors), subsequent research studies explored the
beneficial effects of individual colors to determine which might be
better at causing NO production or release and the accompanying
vasodilation. Studies with visible colors were followed by experiments
with single wavelengths (monochromatic) of non-visible light such as
ultraviolet (UV) and near infrared (NIR).
Once NO is made
available following the ATS’s effect on RBC, and local blood flow
(both arterial perfusion and venous return) is increased, skin ulcers
heal faster and sensory and other nerve functions improve toward
normal (All these events occur through the effect of nitric oxide to
elevate cGMP and the phosphorylation events that follow).
Loss
of sensation, especially in the feet of diabetic patients, has always
been a progressive and irreversible side effect of diabetes; there
was, until the ATS became available for clinical use in 1994, no known
treatment for diabetic peripheral neuropathy.
Since Loss Of Protective Sensation (LOPS) is the leading
cause of diabetic foot ulcers and amputations, saving the foot has
become a goal of all agencies (Federal, for profit, and
not-for-profit) interested in diabetes foot care. One important
recommendation to diabetic patients is to exercise. Exercise is much
easier to engage in if blood flow is restored to near normal levels.
In addition, exercise itself produces NO in blood vessels (by a
process known as “shear stress”) so that once circulation is
restored toward normal levels, exercise helps to sustain the
improvement in blood flow. However, it is quite difficult for a
diabetic patient, with poor baseline blood flow and little or no
sensation in their feet, to engage in this needed exercise.
Use of the ATS now
appears to be a simple way to reverse LOPS (i.e., to restore
protective sensation). Restoration of protective sensation is the
leading way to dramatically decrease the incidence of ulceration and
reduce the number of diabetes-related amputations performed each year.
Associated costs of simply just treating diabetic ulcers, rather than
healing them, should also decrease since the ATS also helps to heal
(not just treat) diabetic ulcers. Importantly the ATS mediated
increase in local NO, besides just increasing blood flow, oxygen, and
nutrient delivery, has other secondary effects.
The ATS mediated increase in circulation restores the ability
of cells such as fibroblasts to secrete growth factors, and NO
enhances cell division so that new cells are formed faster than in the
absence of NO. In addition, the increase in circulation delivers more
white blood cells to the area so that healing and infection control
can be achieved naturally. If needed, antibiotics are also delivered
more effectively to the site of an infection when localized blood flow
is increased. This is a remarkable series of outcomes, all attributed
to increasing local NO at the treatment site.
It is highly
unlikely that we would have been able to draft this series of articles
on diabetic peripheral neuropathy and wound healing if Dr. Furchgott
had not been curious about the effects of light in his laboratory
experiments so many years ago. In fact, even he recognized the
importance of NO to diabetic patients. Dr. Furchgott wrote a lengthy
article in 1998 entitled “Nitric
oxide: from basic research on isolated blood vessels to clinical
relevance in diabetes”, An R Acad Nac Med (Madrid) 115: 317-331.
The Anodyne Therapy System capitalizes on these Nobel Prize winning
laboratory experiments and appears to lead, non-invasively, to a
biologic correction of diabetic circulatory problems that previously
defied any consistent mechanical or pharmaceutical treatment.
Patients with
serious diseases, and even their physicians, are often frustrated with
the slow pace by which basic research is translated into treatments or
cures. This series of articles highlights that such results do occur,
and we encourage everyone to continue to support basic research
conducted by the National Institutes for Health. One never knows where
the next breakthrough will occur. We hope that the information on NO
and diabetes, provided in this series of articles over the last 12
weeks for patients and their healthcare providers, will stimulate
discussion about the importance of NO in ameliorating some of the
symptoms of diabetes.
In conclusion, we
recognize that research continues in the field of nitric oxide every
day and that, in the future, targeted pharmaceutical drugs might be
developed to locally increase nitric oxide.
In the meantime, the Anodyne Therapy System™ is a currently
available, viable approach to locally stimulating NO release so as to
increase circulation and reduce pain, two outcomes that may be of
particular advantage to diabetic patients.
Dr.
Tom Burke received his PhD in Physiology from University of Houston,
Post Doctoral Training at Duke Medical School, He was an Associate
Professor of Medicine and Physiology at the University of Colorado
Medical School. He has authored more than 70 published scientific
clinical articles and has been a visiting scientist at the Mayo
Clinic, Yale University, University of Alabama, and University of
Florida. He is a recognized international lecturer on cell injury and
nephrology.
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